PART NUMBER: K2218. Ford F250/F350 4WD. Radius Arm System w/ Performance Shocks. Performance Shocks ♦ (2) FTS7188 - Front Performance Shock. ♦ (2) FTS7266 - Rear Performance Shock. Order Dirt Logic-FTS220512, Dirt Logic w/ Resi-FTS221162 or Stealth-FTS8046.