SKU: 75165752795

Kythera SA (Semi Auto)

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Description

Kythera SA (Semi Auto)The Kythera has been the most eagerly anticipated products from PolarStar in the past decade. This HPA system is a radical departure from all previous systems that PolarStar has produced since the Kythera does not use a battery, an FCU or any type of electronics. The Kythera is completely mechanical. This means you never have to worry about charging batteries or work with delicate electronics. It also means that the system is completely waterproof.

The Kythera has been the most eagerly anticipated products from PolarStar in the past decade. This HPA system is a radical departure from all previous systems that PolarStar has produced since the Kythera does not use a battery, an FCU or any type of electronics. The Kythera is completely mechanical. This means you never have to worry about charging batteries or work with delicate electronics. It also means that the system is completely waterproof. 


The name "Kythera" (ky-the-ra) was derived from the Antikythera Mechanism which is a mysterious device that was discovered by sponge divers off the coast of the Greek island Antikyther. The mechanism was so advanced in design that scientists have been studying it for decades to discover its purpose. The machine dates from around the end of the 2nd century B.C. and is the most sophisticated mechanism known from the ancient world. Nothing as complex is known for the next thousand years. The Antikythera Mechanism is now understood to be dedicated to astronomical phenomena and operates as a complex mechanical "computer" which tracks the cycles of the Solar System.

For this reason we used the name Kythera for the valve mechanism at the core of a new line of PolarStar mechanical HPA systems. Although it contains very few parts and is easy to install and maintain, the system incorporates a very intelligent design and is unlike anything else on the market. The system was designed as a mechanical system from the ground up and uses a realistic trigger mechanism which can be applied to single-shot, semi-automatic and fully-automatic systems.


The first of these systems is Kythera SA (Semi-Automatic), the semi-auto-only variant for use in AEG gearboxes. PolarStar Filter Fitting now included.


So, what makes the Kythera so unique?

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Realistic Trigger

What sets this system apart from other mechanical systems is the design of its trigger. The trigger mechanism is designed to replicate the function, weight and feel of a real single-action firearm trigger. It feels real because it is real. The hardened alloy steel sears catch and release the stainless steel spool valve in the same way the sears of a real firearm catch and release the hammer or striker. This gives the Kythera trigger the distinct break and reset you would expect to feel when firing a real single action firearm. The trigger mechanism in the Kythera SA is also adjustable, allowing the user to fine tune the weight and over travel. Additionally, the internal firing valve is balanced and the only force applied during firing is the main spring. This means the function and feel of the trigger is independent of input pressure and velocity.

Complete Shot Cycle

The design of the Kythera SA completes a shot cycle on the trigger pull. This gives you the proven closed bolt performance of the Fusion Engine and F2 in a completely mechanical, waterproof system with a realistic trigger. It does not require the trigger to be released before the nozzle chambers the next round and the firing volume is refilled. This occurs automatically and consistently every shot, with adjustable nozzle dwell and return speed.

As the system resets and recharges immediately after firing, it is ready to fire again before the trigger has been released. This means the system can cycle very quickly for faster follow up shots and a lower potential for double feeding.

Extremely Efficient and Consistent

The valve design of the Kythera operates without the need for air to control the opening or closing of the valve. Without a pilot valve, 100% of the air going into the system is fired through the nozzle allowing it to operate very efficiently. In addition to being extremely efficient, the system is also extremely consistent. The valve is released at the same point every shot with the same force applied, regardless of trigger input.

Universal Charging Cord

The steel cord visible at the back of the system is attached to a cocking mechanism for the internal spool valve.  Although the system automatically cocks the spool valve when the system is pressurized, since the Kythera uses a balanced valve, it is possible in certain situations that the valve could stall and needs to be manually cocked. This typically only happens if the system is run completely out of air so that the pressure drops below the operating range of the system. The cord is designed to be either routed through the grip of the rifle for easy access or even possibly attached in some fashion to the charging handle.

 

Easy Installation

The Kythera SA system installs into a standard gearbox as a single assembly and typically does not require any modification to the gearbox. There are no separate parts to install and the only parts needing to be retained from the gearbox is the trigger, spring guide, selector and safety components.


Gel Ball Compatible

The Kythera SA system can be configured for use in Gel Ball firing 7-8mm projectiles.

 

 

Wide Velocity Adjustment Range

The Kythera has a wide operating pressure range of 60psi to 180psi which allows you to fine tune the velocity of the system and tailor for different requirements and applications. Within this pressure range we observed a muzzle velocity of 270 - 500fps w/ .20g using a 6.05x380mm barrel. This lets a single Kythera be used in any role ranging from CQB to Sniper by mainly just adjusting the input pressure from your air rig.


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  • Designed from the ground up as a high performance mechanical HPA system, not a modification of a solenoid operated design.
  • Patent pending valve mechanism provides excellent efficiency and consistent velocity combined with a realistic trigger pull and reset.
  • Completes a full shot cycle on the trigger pull alone which translates into consistent nozzle movement and rapid follow up shots.
  • Adjustable trigger. Adjustments include: Weight, length of pull and over travel.
  • Adjustable nozzle dwell/return speed.
  • Wide operating pressure range of 60 to 180psi.

 

 

**All kits come with configured with the correct trigger linkage, filter fitting, and any additional components needed to convert the specific airsoft rifle model for which the kit is configured. The HPA Tank and Air Rig (regulator and line) needed to operate the system are purchased separately.**

 

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SKU: 75165752795

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4.2 ★★★★★
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Lara Loves Lit
Houston, US
★★★★★ 5
Epic Adventure with FMC coming into her power
Format: Kindle
Honestly, the author, HM Wolfe had me at the dedication: “For my readers. For the ones who suffer silently. You will not break.” About: The Book of Cin takes us on a heart wrenching and inspiring journey of love, betrayal, self discovery and healing where everything Hyacinth thought she knew about the realms - and herself - is turned upside down. As she learns about her own dormant magic, she must also find her courage and make sacrifices to protect her friends as the threat of war hangs over them. My reactions: Holy smokes, this was amazing! First off, I have to say that the trauma Hyacinth experiences from the emotional and physical abuse of her narcissistic boyfriend hit hard for me. It was written so realistically, and I especially appreciate the author’s accurate betrayal of what this type of trauma does to one's self-esteem and character. Her healing journey and growth throughout the story is paced with perfection, and I found myself cheering Cin on every time she reclaimed a bit of herself and discovered newfound strengths. The sexual tension and attraction between her and Landers is the kind of slow burn you crave, and it delivers on making you more than ready for the tension to break. “The only time I want to see you on your knees,” he whispered with a low rumble, “is when those beautiful lips are wrapped around me.” How hot 🔥 is that?! “You are mine.” He said the words not with possession, but in devotion. “You do not belong to me, but I . . . I belong to you.” If you love epic adventures with found family, a morally grey MMC, magic, and an FMC coming into her own power, this needs to be added to your TBR. Oh, and did I mention, they’re dragons?!?!
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Reviewed in the United States on September 14, 2024
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sugar_jean
Port Orchard, US
★★★★★ 4
Great debut!
Format: Hardcover
“I will decimate anyone who tries to hurt you; anyone who lays a hand on you.” DV awareness History erasure Magic suppression Found family Chosen one Slow burn to spice I was happy that there’s a heavy exposure to domestic violence awareness and that Cin found the will and courage to acknowledge and get out of the abusive relationship she was in. She is really working toward taking back her voice, her choice and her power. The story covers themes of loss, betrayal and oppression as well as the power of friendship and having people truly see you. And Landers, our mmc, delicious.
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Reviewed in the United States on June 18, 2025
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The Nerdy Bookshop ✨📚✨
Bozeman, US
★★★★★ 5
Emotional & Powerful Read!
Format: Paperback, Format: Paperback
The Book of Cin by HM Wolfe was such an emotional and powerful read! As the first installment in The Stories Trilogy, it completely hooks you and leaves you desperate for more. I absolutely loved watching the FMC slowly grow into her abilities after years of abuse and struggling with her confidence. It felt raw and real in a way that stuck with me 🖤 This story has everything.. found family, betrayal, and moments of truly heart-wrenching grief. But what I loved the most was the belief that love and chosen family can help heal even the deepest, unseen wounds. Seeing that healing unfold made this journey incredibly rewarding ✨ If you love fantasy with emotional depth, an amazing magic system, character growth, and meaningful relationships, you NEED to pick this one up! 📚🔥
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Reviewed in the United States on March 23, 2026
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Mandy Jo
Whiting, US
★★★★★ 4
Well…
Format: Kindle
I enjoyed the book, it had an interesting plot and magic system. The book is full of smirks, hissing, and crying. OMG the crying! The FMC cries from front to back of the book! I absolutely loved Daggermouth and read this book bc that, but I feel like she had a different editor maybe?! Idk what happened, but this book would have been so much better without the MMC smirking on every page that the FMC was crying on.
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Reviewed in the United States on May 29, 2026
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Asia Young
West Palm Beach, US
★★★★★ 5
Top Book of 2024
Format: Kindle
May Contain Spoilers! Where do I even begin? I'm still in shock of how amazing this book was, how it touched my heart, and now how I have to wait for H. M. Wolfe to write the second. Because those last few chapters...went from 0 to 100 quick. So much new information, new relationships and loss, that now the tides have turned, and we NEED more. This is a fantasy book of love, loss, the power of friendship, and finding one owns strength. TBOC is about Hyacinth whose home is at Asrai’s Academy for Orphans. She was torn between the safety of home or leaving it all behind for a chance at a new life. But when a mysterious messenger appears, whispering rumors of a God among Fae, everything Hyacinth thought she knew about the Realms comes crashing down, and she must now make a new journey. This book ate me up and spit me back out. I was not anticipating the emotions I would feel within these pages. I'm talking I was laughing, then I was swooning, then I was on the edge of my seat, then I'm ready to slap someone, then I'm rooting so hard for certain characters I don't wan to stop, then my heart is broken, then I'm excited af.... it was all an emotional rollercoaster. The last few chapters contained a lot of new information, so of course as much as it doesn't leave off on a complete cliffhanger, I was over here like scraping the bottom of an ice cream cup, wanting more. The magic system starts out ambiguous, but as you continue reading you start to get more and more to build off of and start to piece together the world H. M. Wolfe created. TBOC brings in eight main characters that test alliances, grow in friendships, fall in love, become a team, and even break bonds. The friendship among the girls was everything. Ata is a spit fire, Pria is sweet yet terrifying. The banter and protectiveness these three had for one another made me want to join in with them for breakfast. I liked how there was multiple romances going on at once. Yes we have the main characters, but it just wasn't always about them, and it was great to see how others shifted and grew too. And last the romance, I've never rooted so hard for two characters. We're talking slow burn between them. In the beginning you're not sure how this is all going to play out, but Landers is a tatted, "touch her and die" kind of MMC, which who cannot love that? Hyacinth definitely had to grow within the chapters and learn how to be strong, because sometimes she was making me mad and I just wanted to step in there for her. But Landers was everything she needed and it was so well written, which is why by time you get to the end you only want more of them!
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Reviewed in the United States on September 24, 2024

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