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Description
Ronstan 75mm Single Core BlockProduct Description Ronstan 75mm Single 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 Universal head with full 3 axis articulation Shackle head lockable at 0 or 90 degrees Alloy Rope Wire sheave version also
Product Description
Ronstan 75mm Single 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
Universal head with full 3-axis articulation
Shackle head lockable at 0 or 90 degrees
Alloy Rope/Wire sheave version also available
Measurements
Sheave Ø - 3 in.
Max. Rope Ø - 9/16 in.
Max. Cable Ø - in
Pin Ø - 5/16 in.
M.W.L. - 330 lb.
B. L. - 6600 lb.
Weight - 12.5 oz.
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.
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.
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
Features
Measurements
Sheave Ø - 3 in.
Max. Rope Ø - 9/16 in.
Max. Cable Ø - in
Pin Ø - 5/16 in.
M.W.L. - 330 lb.
B. L. - 6600 lb.
Weight - 12.5 oz.
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.
Applications
Materials
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
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
4.8 ★★★★★
Based on 30 reviews
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Product Reviews
★★★★★ 4
Not a chew toy
Color: red&green
Our dogs love these! The dogs play for about a half hour then they get tired ,they pick it up by the string and toss it around , only important thing, supervise play time !!! This will break if chewed on , this is not a chew toy , put away once your dogs are done with it .
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Reviewed in the United States on January 15, 2026
★★★★★ 2
Fits Cats not Dog size
Color: red&green
Sure these balls are cute, but most definitely not a dog size. I wouldn’t waste your money, unless you own a cat!
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Reviewed in the United States on June 7, 2026
★★★★★ 1
Not durable
Color: red&green
The description says for cats and dogs. My 6lb mini poodle tore it up in less than 40 minutes. The red one worked but the green one wouldnt even turn on. The indicator said it was fully charged but u plugged it in for a short time but nothing. I dont know if i can get a refund or not since the cover on the red one has been completely torn off. I dont recommend this product
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Reviewed in the United States on May 15, 2026
★★★★★ 5
This is an awesome toy for dogs and cats!
Color: red
This is such a cool toy for a dog or a cat. I bought it for my 28 pound Aussie doodle. She’s slightly laid up after an injury recently so I’m trying to come up with things she can play with in the house without excessive running. This totally keeps her engaged and she loves it. But I have to watch her because every once in a while she’ll just catch it and try and chew on the ball! But I’ve been sharing it with my neighbor who has a cat. She’s borrowing it today and her cat loves it too! It seems pretty durable overall but it certainly doesn’t want my dogs’s jaws trying to crack it into. You do hear a humming noise while it’s running but I think that’s to be expected. Mostly I just love how much it entertains both dogs and cats!!
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Reviewed in the United States on March 7, 2026
★★★★★ 5
So cute and entertaining to watch!
Color: pink
Bought for my miniature schnauzer. She didn’t know what to think at first but loves it now. It’s so much fun watching her play and keeps her busy! My dog isn’t much of a chewer and loves the movement/chase of this toy. Wouldn’t recommend for big dogs or chewers as there’s a plastic piece that can come off.
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Reviewed in the United States on January 9, 2026