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Description
Ronstan 75mm Single, Aluminum Rope/Wire Sheave Core BlockProduct Description Ronstan 75mm Single, Aluminum Rope Wire Sheave Core Block Features Class leading performance and sleek, contemporary styling Excellent dynamic and high static load performance Less than half the friction of the nearest competitor Durable aluminum alloy cheek plates Central hub hole can be used as a becket take off or tie up point Durable alloy Rope Wire sheave Universal head with full 3 axis articulation Shackle head lockable at 0
Product Description
Ronstan 75mm Single, Aluminum Rope/Wire Sheave Core Block
Features
Class leading performance and sleek, contemporary styling
Excellent dynamic and high static load performance
Less than half the friction of the nearest competitor
Durable aluminum alloy cheek plates
Central hub hole can be used as a becket take-off or tie-up point
Durable alloy Rope/Wire sheave
Universal head with full 3-axis articulation
Shackle head lockable at 0 or 90 degrees
Measurements
Sheave Ø - 3 in. (75 mm)
Max. Rope Ø - 9/16 in. (14 mm)
Max. Cable Ø - 5/16 in (8 mm)
Pin Ø - 5/16 in. (8 mm)
M.W.L. - 3300 lb. (1500 kg)
B. L. - 6600 lb. (3000 kg)
Weight - 15.3 oz. (432 g)
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 optimization and the cut-away design minimizes 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, minimizing rope wear.
Universal head
The head assembly incorporates a brass bearing washer to provide smooth 360° rotation of the post and shackle. A set screw arrangement allows the head to be locked at 0° or 90°. Shackles are high quality forged grade 316 stainless steel.
Acetal & aluminum sheave options selected models are available with an aluminum sheave which has a deep groove profile specifically made for use with wire.
Applications
Ideal for use on mainsheet, spinnaker sheet, vang, halyard and backstay applications on boats up to 14m (46ft).
General applications on larger yachts.
Alloy sheave models are available for use with wire.
Materials
Sheave: U.V. stabilized acetal or anodized aluminum (AW models).
Cheek plates: Aluminum alloy
Ball Bearings: High compression strength carbon black acetal.
Shackle, post & hub: Grade 316 stainless steel.
Features
Measurements
Sheave Ø - 3 in. (75 mm)
Max. Rope Ø - 9/16 in. (14 mm)
Max. Cable Ø - 5/16 in (8 mm)
Pin Ø - 5/16 in. (8 mm)
M.W.L. - 3300 lb. (1500 kg)
B. L. - 6600 lb. (3000 kg)
Weight - 15.3 oz. (432 g)
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 optimization and the cut-away design minimizes 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, minimizing rope wear.
Universal head
The head assembly incorporates a brass bearing washer to provide smooth 360° rotation of the post and shackle. A set screw arrangement allows the head to be locked at 0° or 90°. Shackles are high quality forged grade 316 stainless steel.
Acetal & aluminum sheave options selected models are available with an aluminum sheave which has a deep groove profile specifically made for use with wire.
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
4.2 ★★★★★
Based on 17 reviews
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Product Reviews
★★★★★ 5
I like it
Good box
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Reviewed in the United States on February 19, 2026
★★★★★ 3
Small but Functional
Small, but works for what little bit of jewelry I wear!
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Reviewed in the United States on August 12, 2025
★★★★★ 5
Awesome
Organization is good fit for all my jewels
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Reviewed in the United States on March 26, 2026
★★★★★ 5
Great value, great product!
I use this as a home jewelry box - I don't wear a lot of jewelry, so it fits my needs perfectly. Its pretty lightweight and would be good for travels as well. The outside is leather-like and seems to be waterproof so far. I use the first layer for jewelery and second layer to store my hairclips and pins. I've had it for a few months and it seems to be great quality and durable! Definitely a good value as well because I've seen similar jewelry boxes sold at popular retail stores for over $30.
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Reviewed in the United States on January 21, 2026
★★★★★ 5
Lovely Slate Gray Jewelry Box
I just received this Slate Gray jewelry box. It's really quite lovely and just the right size for my granddaughter's vanity. I'm really excited about giving it to her, for her 12th Birthday, to hold her better jewelry. It's so nice I'm going to order another one for my other Granddaughter's Birthday.
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Reviewed in the United States on December 5, 2025