The Ready LIFT 67-2195UB M16 Round 390mm Long U-Bolt Kit is designed to be used with 5" rear lift blocks if your 2005-2010 Ford F250/F350 is a camper package vehicle. For Use With Single Rear Wheel Trucks Only. We are making these longer U-bolts available to our customers who have purchased a 5" block kit and discovered the U-bolts supplied with the kit are not long enough due to the truck having a Camper Package rear suspension. Trucks with Camper Package rear leaf springs require longer U-bolts due to the upper overload spring. Kit includes four new M16 390mm long U-bolts and eight crush nuts.