Ronstan Series 55 Ball Bearing Orbit Block - Single - Becket - Swivel Head [RF55110]
SKU: 52222429116

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

Sale price$45.52 Regular price$50.58
Save 10%

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 8 - Jul 13

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

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: 52222429116

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.7 ★★★★★
Based on 569 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
A
Verified Purchase
AmazonianShopper
Draper, US
★★★★★ 5
Lightweight & good price for quality
Size: Medium, Color: Camel Heather
Lightweight as other reviewers noted. I purchased camel color & oatmeal heather color for travelling on long plane ride while wearing with leggings. Ribbed cuffs and hem, which I like. V neck just right on me. Cotton blend knit, good. Color as expected. Sleeves long enough (yay!) Probably will pill eventually, but I'm not worried about it at the moment. Doesn't look cheap, which is nice for inexpensive top. I don't wear leggings a lot, so I don't think these will get lots of use, so until they start looking pilly I'll use them when I need to. I'm 5'7" & weigh 115 lbs, 34 A, and 37 hip. Size small in both colors draped perfectly, looser fit style, not clingy or tight around the bum, which is what I wanted. It doesn't look baggy or boxy on me, but I'm relatively slim so it may not fit as I've described for those with bigger bustline and/or waistline measurements and/or tummy. I think it is flattering on me, so I'm keeping them. I would say the size S it runs slightly big for my body type if that helps. Everyone is different even when we wear the same size! After reading reviews I purchased S and M sizes. I returned the mediums as they'd be way to baggy on me and too big across the shoulders.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 10, 2023
D
Verified Purchase
Dee
Chelsea, US
★★★★★ 5
Fantastic Sweater for the Price!
Size: XX-Large, Color: Charcoal Heather, Size: XX-Large, Color: Charcoal Heather
I'll admit it, I was VERY skeptical about buying an Amazon Basics Sweater. I was sure the sizing or material or something would have to be off as the sweater was very reasonably priced. I was very happily proven wrong. This sweater is great. It's a v-neck, the most flattering fit for me and the v is not so deep as to be indecent, I can wear it easily and comfortably to work without a camisole underneath - even as a rather busty gal. The material is nice and soft. It's not cashmere soft, but it feels much better than a $20 sweater. It also washes pretty well, I've washed my sweater a few times and have had no shrinkage. I don't tend to put sweaters in the dryer, I air dry them - so that probably helps as well. After 2 or 3 washes, there is a slight amount of pilling underneath the arms where the sweater rubs against itself, but not a large or greatly noticeable amount. The sweater is also pretty long. I'm not sure I'd wear it as a tunic (with leggings), but I do wear it with skinny jeans comfortably and don't worry about it riding up in the back. I found it to be true to size. It's meant to fit a little looser and I like that. It's a great comfy sweater and I get a lot of compliments on it. This is a great value for the price - I will definitely try other Amazon Essentials. I own it in three colors (and counting). Update a year later - I just purchased 3 more of these sweaters for the upcoming winter. They are some of my absolute favorites. They are flattering even if you have a bit of tummy and not too heavy. These have withheld multiple washing with minimal beading (or whatever you call it when the little fuzzy balls appear at the high friction points). I have done some shaving on the sweater and I'm pretty fastidious about washing them on gentle and letting them air dry (like I do with most of my sweaters).
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 15, 2019
J
Verified Purchase
Jessica
Boise, US
★★★★★ 3
Color not as pictured.
Size: Medium, Color: Dark Green
The color was not the same as picture. I was hoping for a nice jewel tone true green, but it is more of a light green. I still love the fit of it, and the color isnt ideal for me, but it isn't horrible. If I decide I really hate the color, it'll look great on my mom.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 5, 2026
C
Verified Purchase
christy
Lexington, US
★★★★★ 5
Great shirt, nice comfortable fit
Size: XX-Large, Color: Charcoal Heather
Really comfortable fit and looks good, nice colors, bought a few different colors after the first one I ordered
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 18, 2026
A
Verified Purchase
Alicia
Los Angeles, US
★★★★★ 5
Great bang for your buck!
Size: Medium, Color: Green
The price point on these Amazon sweaters is fantastic! Great quality, great length for us taller women (I'm 5'8) and they have held up to plenty of washing and drying. Love the variety of colors available. Can easily be dressed up or down. They are a little thin, but not sheer. Perfect for packing on a trip because they take up minimal space. The perfect year around sweater for any season.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 26, 2026

recommand products