Intended for use in extreme conditions, these bearings are superior because they last many times longer than stock. The "PRO-PACK" is a top grade double sealed bearing that has been specially filled with the highest quality "moly" grease available. This "moly" (molybdenum disulfide) grease offers superior shock load protection AND water resistance. Exclusively from CBR Bearing Company, the "PRO-PACK" is the best wheel bearing available, and the choice of the professional rider or serious enthusiast. It carries an industry first LIFETIME WARRANTY to the original purchaser!