All Toyota kits include special heavy-duty pistons, which are designed and manufactured to perform flawlessly under the extreme heat and PRESSURE associated with turbocharged engines. Ideal for both street and serious competition, these pistons are loaded with extra features such as annular pin hole grooves with double forced oil holes to prevent pinhole galling, and taper lands to prevent scuffing. Extra thick lands for superior ring groove support under extreme pressure are made possible by intersecting the ring groove with the pinhole and using ROSS Oil Ring Support Rails. 4340 taper bore, hard-chromed extra heavy duty pins, along with Ross Racing Rings are also included. Pin information can be found here., and ring information can be found here.