SKU: 5750437443

Ronstan Series 45 Core Block™ - Single - Swivel Shackle Head

Sale price$64.48 Regular price$71.64
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Ships within 48 hours · Estimated delivery Aug 8 - Aug 13

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Description

Ronstan Series 45 Core Block™ - Single - Swivel Shackle HeadSeries 45 Core Block Single Swivel Shackle Head Core Blocks are a true all round solution. A tuned 2 stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets,

Series 45 Core Block™ - Single - Swivel Shackle Head

Core Blocks™ are a true all round solution. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing.

Universal Bearing
Dynamic and high static load performance

The Ronstan Universal Bearing incorporates our proven 2-stage bearing system

Stage 1 - Under moderate loads, Acetal ball bearings ensure minimum friction.

Stage 2 - Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless steel race takes over, maintaining low friction performance.

Additionally the ball bearings are configured to act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn't perfect. Particularly important for cheek blocks.

Alloy Cheek Plates
Block cheeks are manufactured from the highest quality alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings. Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear.

Features:
  • High dynamic and static load capacity
  • Efficient 2-stage bearing system
  • Ball bearings to counteract side thrust loads
  • Class leading performance and sleek, contemporary styling
  • Durable aluminium alloy cheek plates
  • Central hub hole can be used as a becket take-off or tie-up point


Applications:
  • Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 10M (33')
  • Various control line applications on larger yachts
  • Alloy sheave models are available for use with wire


Materials:
  • Sheave: U.V. stabilized Acetal
  • Cheek body: Aluminium Alloy
  • Ball Bearings: High compression strength carbon black Acetal
  • Shackle, head post & hub: Grade 316 stainless steel


Specifications:
Sheave Ø: 45mm(1-3/4")
Max. Rope Ø: 12mm(1/2")
Pin Ø: 5mm(3/16")
M.W.L.: 700kg(1,540lbs)
B. L.: 1,400kg(3,090lbs)
Weight: 104g(3.6oz)
Manufacturer : Ronstan
Manufacturer Part No : RF44100
UPC : 9316800466153
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 5750437443

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Daniel C
Grantham, US
★★★★★ 5
New Favorite Work Shoe
Size: 9.5, Color: Black/Ivory
These Cole Haan Grand Crosscourt Daily shoes have quickly become my new favorite work shoes. They’re incredibly comfortable right out of the box, with just the right amount of cushioning and support to get through long days on my feet. I love that they look sleek and professional while still feeling casual enough to wear anywhere. The build quality is top-notch—durable materials and solid construction that make them feel like they’ll last a long time. Overall, these shoes strike the perfect balance between comfort, style, and practicality. I can honestly say I look forward to wearing them every day. Highly recommend for anyone who spends a lot of time on their feet but doesn’t want to sacrifice style.
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Reviewed in the United States on February 9, 2026
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Edward Diaz
Lake Worth, US
★★★★★ 5
Well Made for price and style
Size: 10.5, Color: Black/Ivory
Great fit and very flexible. I also recommend buying shoe savers when purchasing this product. To help with toes wrinkles. The pair itself is stylish and very comfortable. Any purchase of this product will be greatly satisfied.
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Reviewed in the United States on April 16, 2026
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Pierre
Lexington, US
★★★★★ 5
Nice shoes
Size: 11.5, Color: Black/Ivory
The are very comfortable, and look great.
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Reviewed in the United States on April 8, 2026
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Jeffrey Clemons
Waukegan, US
★★★★★ 4
Comfortable
Size: 9.5, Color: British Tan/Ivory
Great foot support. Wore all day with not foot or back pain.
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Reviewed in the United States on April 29, 2026
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Walter R Moore
Cuba, US
★★★★★ 5
Quality at affordable prices.
Size: 11.5, Color: British Tan/Ivory
Best old guy shoes. They look great and have support for feet. You don't want cheap department shoes. You will pay for that in your later years.
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Reviewed in the United States on April 11, 2026

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