Premium base materials ensure seals are made to OEM specifications and tolerances for steady, guaranteed quality and superior durability. ProX Racing Parts Racing Parts crankshaft oil seals are assembled in sets for an easy and cost efficient OEM replacement. Manufactured at the leading OEM factories in Japan. Can be used in combination with all other ProX Racing Parts Racing Parts or OEM crankshaft related products. Fits: Yamaha YZ 250 1998.