Packed with a heavy duty premium marine grease and an addition of a special complex thickeners which allows it to be virtually waterproof. Nitrile Butadiene Rubber Double-lip oil seals; prevent abrasives, corrosive moisture and other harmful contaminants from entering bearings. Also to keep any moisture out, we have gone from 30% grease filling to a 60% for harsh conditions. Our Factory-Links ball bearings are specially designed for an Off-Road use. Special V-groove on the inner race for a better resistance to water intrusion. Provides unsurpassed rust and corrosion protection.