Hairline cracks in a piston do not show until the circuit is under pressure on the road.U150 6 PIECES PISTON KIT STK. The sealing surface is produced to the bore it wipes.Bore finish is what the seal wipes against for the life of the unit. Shipping weight is 4.4 lb.The parts list below is exactly what ships. Compare it against your teardown before ordering.REMCO has supplied automatic transmission parts since 1991, and every order ships with its part listing so the receiving technician can check what arrived against what was ordered. Transmission Piston Kit for U150 - replacement component designed for proper fit and function Designed to support proper clutch apply pressure, stroke and sealing during piston and seal work Package Includes: one transmission piston kit as described, supplied loose for piston and seal work Bonded rubber lip seals on a steel or aluminum piston body - designed for dependable service in the intended application. Ships at 4.40 lb, 16x16x2 in Intended for builders correcting apply pressure loss. Lubricate the lip seals before assembly and seat the piston square in the bore What's in the box1 x Piston Kit, U150 U151 6 PIECES STKCompatible vehiclesFits ES 300 [02-03], ES 330 [04-06], RX 330 [04-06], RX 350 [07-09].