4L60E Alto wideband /power band ( 67mm wide with sonnax heavy duty 1-2 accumulator spring. also comes with an upgraded 1-2 alloy accumulator piston ( 6mm pin size hole approx ) that adds a firmer 1-2 shift and 3-4, adds durability due to its width, and also has stronger anchor points, stops reverse drum surface warp, a must-have in all V8s. The redlining has even more bite than the dark high-energy lining… The factory plastic piston always wears or cracks, and the alloy upgrade has a long shaft hole for more support 12-month warranty against breakage!