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Description
Ronstan 45mm Single Core BlockProduct Description Ronstan 45mm Single Core Block 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 aluminum alloy cheek plates Central hub hole can be used as a becket take off or tie up point Measurements Sheave 1 3 4 in. (45mm) Max. Rope 1 2 in. (12mm) Max. Cable in (mm) Pin 3 16 in. (5mm) M. W. L. 1540 lb.
Product Description
Ronstan 45mm Single Core Block
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 aluminum alloy cheek plates
Central hub hole can be used as a becket take-off or tie-up point
Measurements
Sheave Ø - 1 3/4 in. (45mm)
Max. Rope Ø - 1/2 in. (12mm)
Max. Cable Ø - in (mm)
Pin Ø - 3/16 in. (5mm)
M.W.L. - 1540 lb. (700kg)
B. L. - 3090 lb. (1400kg)
Weight - 3.6 oz. (104g)
Product Information
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.
Applications
Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 10m (33ft).
Various control line applications on larger yachts.
Alloy sheave models are available for use with wire.
Materials
Sheave: U.V. stabilised Acetal
Cheek body: Aluminium Alloy
Ball Bearings: High compression strength carbon black Acetal
Shackle, head post & hub: Grade 316 stainless steel
Features:
Measurements
Sheave Ø - 1 3/4 in. (45mm)
Max. Rope Ø - 1/2 in. (12mm)
Max. Cable Ø - in (mm)
Pin Ø - 3/16 in. (5mm)
M.W.L. - 1540 lb. (700kg)
B. L. - 3090 lb. (1400kg)
Weight - 3.6 oz. (104g)
Product Information
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.
Applications
Materials
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- 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
4.3 ★★★★★
Based on 1555 reviews
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Product Reviews
★★★★★ 5
Very good
Color: 01-black, Size: Small
It looks so good on my bf, he really like it. The quality is so perfect.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 15, 2026
★★★★★ 5
Good quality
These fit so well material is very tick nice for winter they have all different colors and it’s so comfy it’s really good value for your money for that level of thickness
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Reviewed in the United States on September 30, 2025
★★★★★ 5
Buy it
If you're looking for a comfortable thick and nice turtle neck this is the one. It's nice and form fitting nice weight to it to keep you warm. But not to thick that you cant just wear it on a regular sunny day if you wanted. The design pattern Is also very nice. Can dress it up or down. I bought the black and then immediately bought the rust orange color for my friend once he tried on mine he wanted one immediately so I gifted him one. He loves it. Definitely worth the buy. Excellent quality. I bought a Large 5"11 165lbs
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Reviewed in the United States on December 21, 2024
★★★★★ 5
What you see is what you get!
Color: 01-black, Size: Large
Fits great, fabric is amazing, turtle neck fits tight, and the quality is amazing!
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Reviewed in the United States on February 11, 2026
★★★★★ 4
A true turtleneck that retains a snug high neck.
Color: White, Size: X-Large
I've found this brand to have gotten better over the years as far as offering the American market what it needs in terms of realistic sizing. I only wish they'd realize that there are a lot of us who are long in the back and arms where my only choice is to go a size up and sacrifice a slim fit for sleeves that are long enough plus a back that doesn't go up past my waist just because I reach up for something, that and I like to be warm. So these are such nice quality turtlenecks that it's hard to complain about but maybe the company will read this. The snug neck stays up is plus number one since that's why I'm buying a full neck. They come with very nice weaves in the fabric, good enough for casual or formal wear. Finally the warmth you seek is there but I've worn them in what most would think isn't the right temp for a turtleneck. Also they have them in white! Yes, a lot of others just don't for reasons I can't fathom, and the pic you're seeing is accurate, these will form to your shape without being ridiculously thin material. Several washes later and they are as fine a garment as when I first wore them. I've only found one other brand that compares to these but it's much more expensive, COOFANDY is affordable in these times of expensive everything. Warm but also a lightweight shirt, I've gotten them really dirty with actual dirt and it washes out so well you'd never know it. Don't let my taking off one star stop you, try one yourself and you'll be coming back for more.
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Reviewed in the United States on July 30, 2025