SINGLE BALL BEARING PULLEY WITH BECKET ALLEN A.378BB SINGLE BALL BEARING WITH INGLEFIELD CLIP A.178 - 74BB SINGLE BALL BEARING WITH INGLEFIELD CLIP A.178 - 74BB Single Ball Bearing With Inglefield Clip - The Allen classic dinghy blocks are manufactured from nylon and are available with either a plain bearing system or ball bearing system. Originally designed for the Laser dinghy mainsheet system but this classic block has also become the block of choice for many other dinghy mainsheet systems. SINGLE BALL BEARING WITH INGLEFIELD CLIP A.178 - 74BB