A904 / 42RE / 44RE / 42RH / 44RH Steel Front Drum & Aluminum Piston Kit. The drum is stronger and safer than the O.E.M. cast iron drum. Made from 1040-1045 billet steel. Piston is made from 6061-T6 billet aluminum and comes with anti-spin locking tabs. Will hold up to 5 frictions. Dual feed/apply passages. 2- solid sealing rings. The drum and piston have been made 28% larger in the piston apply area = more clamping force.