Midrange blocks robust construction makes them ideal to handle the high loads found on medium and large offshore boats. Free-rolling Delrin? ball bearings, sheave and sideplates UV-stabilized with carbon-black additive for maximum protection. A stainless steel sidestrap wraps across the block head for increased strength and safety. The wide-diameter 3.00 in (76 mm) ball bearing sheave accepts 9/16 in (14 mm) line. High-load Midrange blocks use Torlon? ball bearings.