Narrow high load sheaves in mastheads improve sail handling, speed sail changes, and allow the use of smaller , lighter halyard winches.Used in steering systems, these sheaves return "feel" to wheel-steered boats.These sheaves combine sideload-carrying balls with a Teflon composite bushing for radial loads. High-load bearing system Narrow width Lightening holes Installation requires clamping or securing the inner race Made of 6061-T6 aluminum