- Fibertech Day Cab Conversion Basic Kit for Ultra Cab or Flat TopStarting at $1,936.39FB-PBK-2U-XB-GPeterbilt Ultra Cab Basic Flat Panel Day Cab Kit Basic Conversion KitStarting at $1,008.36FB-PBK-U1-B-GPeterbilt Delux Ultra Cab Flat Panel Day Cab Kit Deluxe Conversion KitStarting at $1,512.03FB-PBK-U1-D-G