SKU: 95590616037

Ronstan Series 55 Ball Bearing Orbit Block - Single - Becket - Swivel Head [RF55110]

Sale price$45.52 Regular price$50.58
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Description

Ronstan Series 55 Ball Bearing Orbit Block - Single - Becket - Swivel Head [RF55110]Series 55 Ball Bearing Orbit Block Single Becket Swivel Head Lightweight Kilogram for kilogram of working load, BB and RT Orbit Blocks are the world's lightest. The unique orbital design allows the bearing to only be in the active areas of the floating sheave. This minimises the mass of the inactive return race and hub. Weight and bulk are further reduced in the different block configurations. The ball bearing single and becket block has a through

Series 55 Ball Bearing Orbit Block™ - Single - Becket - Swivel Head

Lightweight
Kilogram for kilogram of working load, BB and RT Orbit Blocks™ are the world's lightest. The unique orbital design allows the bearing to only be in the active areas of the floating sheave. This minimises the mass of the inactive return race and hub.

Weight and bulk are further reduced in the different block configurations. The ball bearing single and becket block has a through-sheave becket arrangement. The result? The lowest weight possible.

Multi-sheave blocks have only single intermediate cheeks and an ultra-light and efficient head arrangement. This gives a 30% weight saving advantage over the nearest competitor. Other brands just link together their single blocks. This results in unnecessary double cheeks between each sheave, held together by a heavy steel channel across the top of the block.

Highest Working Load In Its Class
The orbital ball-bearing arrangement gives the largest possible bearing race diameter. This maximises load performance. The proven Ronstan 2-stage bearing system features high compression grade acetal ball bearings and a secondary full-contact bearing. This gives minimum friction across the full working load range.

The floating sheave and bearing system is supported by a fiber-reinforced load frame. The design was computer modelled to be stress optimised. The Dyneema® Link is produced from FSE Robline SK75 fiber, which is 10 times stronger and lighter than steel, and provides the final connection from the block to the load point.

Features:

  • Ultra Lightweight
  • Low friction 2-stage Orbital ball bearing system
  • Highest working load in its class
  • Low profile and compact
  • High performance cleating
  • Swivel shackle head for unlimited block rotation
  • Stainless steel shackle head for ultimate durability and compatibility with harsh fixing points
  • Ultra low profile integrated becket


Applications:
  • Mainsheet systems on dinghies, sportsboats and small keelboats to 9M(30')
  • Spinnaker sheets on dinghies, sportsboats and small keel boats to 9M(30')
  • Halyard, Vang and Backstay application on boats to 8M(26')
  • Control line applications on larger yachts
  • Ideal use for mainsheet systems and spinnaker sheets on dinghies, sportsboats and small keel boats to 9M(30')
  • Also ideal with halyard, vang and backstay applications on boats to 8M(26')
  • Spinnaker sheets on sportsboats and small keel boats (lateral lead blocks)
  • Control line applications on larger yachts


Materials:
  • Ball bearings - High compression strength carbon black Acetal
  • Stage 2 bearing - Carbon fiber reinforced, PTFE impregnated Nylon
  • Frame/Cheeks - Toughened, glass fiber reinforced Nylon
  • Rope Link: UV stabilized, multi-strand impregmented SK75 Dyneema®
  • Sheave: Carbon fiber reinforced, PTFE impregnated Nylon
  • Head fitting: Grade 316 stainless steel.


Specifications:
Sheave Ø: 55mm(2-5/32")
Max. Rope Ø: 10mm(3/8")
M.W.L.: 500kg(1,100lbs)
B. L.: 1,000kg(2,200lbs)
Weight: 88g(3.1oz)
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: 95590616037

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Joseph J
Massapequa, US
★★★★★ 5
Stylish, comfortable, and very practical
Color: Black, Color: Black
This chair is both cuteand funtional. The wide seat is super comfortable, especially for sitting cross-legged, and the flip-up arms are really convenient. I also like the side pockets for small items. It rolls smoothly, feels sturdy, and was easy to asssemble. Perfect for a home office or vanity setup.
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Reviewed in the United States on April 20, 2026
A
Verified Purchase
Angeline
Whiting, US
★★★★★ 5
Nice office chair
Color: Beige
I recently purchased this chair for my home office setup. This chair is very comfortable and feels sturdy right out of the box. The seat cushion is thick and supportive, the back provides good support. I really like the flip-up armrests, which make it easy to slide the chair under my desk. Assembly was simple and didn't take long. Overall, it's a solid, well-built chair and a great value for the price.
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Reviewed in the United States on March 15, 2026
B
Verified Purchase
Ben McCurdy
Chelsea, US
★★★★★ 4
Seat width short (Not tall people friendly) Very nice otherwise.
Color: Beige
I like the chair a lot. It’s very sleek and modern. One problem I have with it tho is the width of the seat. I am 5’9 and not necessarily a petite woman and when I do sit cross cross I seem to hang off the front. I do like that I can sit cross cross even with the sides of the chair up but the fact that I hang off the front is a bit annoying. There are plenty of other ways to sit on it tho and being able to maneuver it to where I can sit different ways is nice. I would say that this chair isn’t exactly tall people friendly. Also pay attention to the height and width of your desk because it isn’t exactly universal to fit under a normal desk. It is also super easy to put together and instructions are clear. Also as expected the back of the seat is a bit short and personally for me I like that a lot but word of caution for others that want the back of the chair to go up their entire back. I like it shorter because I’m able to sit sideways and have one side of the chair up and the other down and using the back rest as an arm rest. I did just buy it and am slightly concerned for it to not last purely because the manual said not to use it if it squeaked of creaked and it does both of those things. But I will still be using it until it breaks or it’s life span ends. It also seems very easy to clean the crevices are very short and you are able to wipe things out with ease.
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Reviewed in the United States on June 10, 2026
A
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Amazon Customer
Port Orchard, US
★★★★★ 5
Really comfortable upgrade from my old desk chair
Color: Beige
My old desk chair had been getting pretty uncomfortable, so I decided to replace it with this white one. After using it for a few days, I can definitely say it’s been a really nice upgrade for my workspace. My old chair was starting to feel stiff and uncomfortable after sitting for a while. This one is a lot wider and softer, which I really appreciate. Sometimes I sit cross-legged when I’m working on my laptop, and this chair actually has enough space to do that comfortably. The flip-up arms are also really practical. When I’m not using them, I just flip them up and push the chair under my desk. My workspace feels a lot less cramped now. The wheels roll smoothly and the height adjustment was easy to set up. I also didn’t expect to use the side pockets much, but I’ve been keeping a notebook and my tablet there, which is actually pretty convenient. I mainly bought the white color because I wanted something simple for my home office, and it looks really clean in the room. After switching from my old chair, working at my desk has been a lot more comfortable. It’s been great for longer work sessions, and overall I’m really happy I decided to get this one.
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Reviewed in the United States on March 16, 2026
K
Verified Purchase
Kareen
Bozeman, US
★★★★★ 5
Great Buy
Color: Black
Easy to assemble, very comfortable and stylish! Wheels dont roll too easily but thats an easy fix so overall very happy with this
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Reviewed in the United States on April 28, 2026

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