Harken Big Bullet Blocks Low-friction Bullet blocks lead control lines aft. They are compact and lightweight, with fast trim and release under high or low loads. A range of styles lets these blocks adapt to almost all control line applications. Free-rolling Delrin® ball bearings, sheave and sideplates UV-stabilized with carbon-black additive for maximum protection. Wire Bullet blocks use roller bearings to carry higher loads and feature Hardkote-anodized Teflon® impregnated aluminum sheaves for strength and corrosion resistance. Mast exit blocks with cams used for halyard controls and under boom mainsheets. The 140 is designed for under-boom mainsheets or for spar-mounted halyards and control lines and pivots for a fair lead. The 141 is ideal for control lines. Use for: Outhauls Vangs Barberhaulers Cunninghams Traveler controls Furling line leads Flag halyards