MB-A Features: Solid steel rod dip handles welded to a 3 sided face plate for a secure grip on either the Valor Fitness BD-7 or BD-33 Power Racks. The solid steel rod is positioned completely through the main frame uprights, allowing a safe locking mechanism to the frame. The correct position of the handles will be placed so you the user is on the inside of the unit. MB-A handles only fit the BD-7 and BD-33 Power Racks. MB-B handles are 2.5" x 2.5" and will fit Valor Fitness BD-7, BD-33, BD-11 or BD-41 Power Racks.