Synergy Mfg Heavy Duty Front Ball Joints for Jeep Wrangler JK - Dana 30 & Dana 44 # 8009-12-01 (1 upper and 1 lower) Fully greasable metal on metal design eliminates the stock style nylon liner for improved performance and durability Larger than stock ball joint stud made from 4140 steel with an induction heat treated bearing surface for smooth operation and maximum life Ball joint boot is made from tear/wear resistant silicone polyurethane 12 Month Unlimited-Warranty Includes (1) upper and (1) lower