Ultima | Rear Shock Absorber Inboard 4WD Heavy Duty | Ford F-250 F-350 Super Duty 2001-2007 | 400025Ultima Rear Inboard Heavy Duty Gas Shock Absorber (Single) for Ford F 250 F 350 Super Duty 4WD 20012007 The Ultima Rear Heavy Duty (HD) Gas Shock Absorber (400025) is the dedicated inboard shock for the powerful Ford F 250 and F 350 Super Duty 4WD models (20012007) that utilize a quad shock rear suspension configuration. This robust, gas charged unit is specifically tuned to manage the demands of heavy towing, hauling, and serious off road use,