" through what appears to be clever engineering, only the loaded portion of the "floating" aluminum sheave comes in contact with the ball-bearing arrangement. This makes for smooth trimming and blazingly fast sheet runs at the weather mark and late dips" From Dave Reed's Sailing World Review . Read the Sailing World Review of this Block These are easy to use as the ratchet function engages automatically when there is enough breeze. The ratchet auto disengages in lighter air or when easing for the run. Unlike competitors this can also be switched on and off. Now these auto/manual ratchet blocks come with a stainless steel swivel shackle for ultimate durability. Sheave Diam. 2 5/32 in. Max. Rope Diam. 3/8" / 10mm Max. Working Load 550 lb Breaking Load 1430 lb Weight 2.8 oz Read a review of this block RF56100Price: $100.18Sale price: $85.16 Ronstan Stand up Boot for Orbit Blocks RF2455Price: $20.71Sale price: $17.60 Harken Stand up Spring for Dinghy Main Sheet Blocks2" X 7/8" Spring works for the Main sheet blocks on the Laser®, Sunfish®, Otimist and many other small dinghy main sheet blocks. H071Price: $1.75Sale price: $1.49 Harken Stand Up Boot Made of durable flexible PVC, stand-up boots hold blocks up without snagging lines. The 370 fits up to 75 mm blocks. H370Price: $17.85Sale price: $15.95 WE SHIP WORLDWIDE! We charge the actual cost of shipping. You may email us for a shipping cost estimate. Send us email intensitysails(at sign)gmail.com US$10 MINIMUM ORDER