Harken 16 mm Air Block with rubber O Ring can be used as the "dingleberrys" which are the turning blocks at the mast for the outhaul as well as the block at the clew attachment to the sail. Either our shackle or the clew hook. Description Single Sheave -dia. (in) 5/8 -Length (in) 1-1/8 -Weight (oz) 1/3 -Max. line dia. (in) 7/32 -SWL (lb) 250 -Breaking strength (lb) 1200 404Price: $18.60Sale price: $16.95 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