SKU: 95113763292

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 Jul 28 - Aug 2

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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 : 45mm(1-3/4")
    Max. Rope : 12mm(1/2")
    Pin : 5mm(3/16")
    M.W.L.: 700kg(1,540lbs)
    B. L.: 1,400kg(3,090lbs)
    Weight: 104g(3.6oz)

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: 95113763292

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4.1 ★★★★★
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Siobhan Smith
Grantham, US
★★★★★ 5
Super soft and comfortable!
I haven't bought new underwear in forever. I used to wear thongs, but now find them incredibly uncomfortable. The last few times I've tried to buy new underwear, the sizing was either way off (I'm a medium, but gave up after having to return them for a large and then extra large) or the quality was horrible (two brands stretch waaaay out and they can fall down while wearing them (I have larger ass-ets, so they shouldn't start to slide down during use). I tried these after buying some bamboo pyjamas and I love them! They are incredibly soft, comfortable, and stretchy. I can use them all day, and they work well, whether I'm lounging on the couch or wearing them under my spandex shorts at the gym, they don't ride up or slide down. They are both comfortable and look sexy, while providing support in all the right places. I haven't had them too long, so I can't speak on the durability, but they appear to be of good quality and I plan to order more, this time without the band.
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Reviewed in the United States on November 13, 2025
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Mariel
Lake Worth, US
★★★★★ 5
Well made, light fabric. Waist doesn't roll.
These bamboo underwear really do keep you cool. They fit true to size, and wear easily. the wide elastic waist band doesn't roll on me. They are comfortable to wear, washed and dried easily. The material has some stretch to it, but not a lot. Well made, no stray strings. Perfect fit for me. Just what I was looking for.
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Reviewed in the United States on May 17, 2026
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Finngirl
Fort Morgan, US
★★★★★ 5
Good quality, smooth feel
I got these briefs so recently that have washed just one pair so far. First off, these are very comfortable, the material is soft & bordering silky, good quality sewing. Wash well and minimal if any shrinkage. They do come a bit wrinkled from the dryer but hey, these are underwear and will go on smoothly. If it were a t-shirt, I would look sloppy. I feel the sizing is accurate. No rolling and these don't announce themselves under clothing. Planning on getting more of these boxers and replacing my old panties.
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Reviewed in the United States on January 31, 2026
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Skurtzo
Houston, US
★★★★★ 4
A little snug on the thighs
Size: Medium, Color: Multicoloured G (5-pack)
Super comfy, soft and thin. For reference, I'm 5'6", 135, athletic build. I bought medium. I almost returned them because I thought they were a bit too snug on my thighs, and my thighs are not large at all. I was concerned about panty lines under snug clothing. But, because they're thin, I figured they would probably stretch, so I kept them. So far, I've only worn them under a night shirt, but they're super comfortable and they dont ride up at all. Very nice, but if your thighs are a little thick, you probably won't like them.
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Reviewed in the United States on August 29, 2025
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Shanna
Whiting, US
★★★★★ 5
Functional + Sexy
Size: Small, Color: Multicoloured E-(5-pack), Size: Small, Color: Multicoloured E-(5-pack)
Not only do these feel good, my husband can’t keep his hands off me. They fit so good and are soft. I change into these to sleep but also just use them as shorts to wear around the house. They’re comfortable and don’t slide around. I got a size small and I’m 100lbs.
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Reviewed in the United States on April 13, 2026

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