Harken^® Big Bullet Block Single is designed for all control applications on smaller boats where up to 3/8" (10 mm) line is used. Compact and lightweight with a sheave diameter of 1-1/2" (38 mm), these blocks have a fast trim and release under both high and low loads. This low-friction Big Bullet Block leads control lines aft and is ideal for vangs, outhauls, cunninghams, spinnaker controls, traveler controls, barber haulers and more.