Bosch 3421 Premium FILTECH Oil Filter Bosch recommends the use of Castrol motor oil Exclusive FILTECH media technology screens out more harmful contaminants for greater engine protection Strong steel base plates and housings prevent warpage, leaks, and poor fit Silicone anti-drainback valve ensures a supply of clean oil when the vehicle is started High lubricity gasket design provides a tight seal, yet allows for easy removal