Prothane Suspension Parts incorporate a special urethane formula, precise engineering, and -consequently- a lifetime guarantee that is second to none. You'll find unique design methods such as splined bores in Prothane's Suspension Parts that guarantees years of squeak free operation. Prothane even includes their own "Super Grease" with each of their parts that requires lubrication, so you'll be sure your suspension parts will last for years to come. When you install Prothane Bushings you'll understand why they're the first choice for mechanics both professional and DIY alike.