Single Ball Bearing 38mm Block With Inglefield ClipThis is an upgraded version of the classic Laser mainsheet block used as the rear mainsheet block attached to the traveller block of the Laser. Typically paired with the traveller block A.178-74BB.This block is Laser class legal. Manufactured from nylon and features a ball-bearing sheave for reduced friction.Originally designed for the Laser dinghy mainsheet system this classic block has also become the block of choice for many other dinghy mainsheet systems.