Dye UL-I Barrel BackThis is the Dye UL I Barrel Back only. You will need three pieces in total to make a complete Dye UL I barrel. #1 The Dye UL I barrel back, #2 The Dye UL I barrel tip, #3 The Dye UL I insert (or a PWR compatible insert). This Dye UL I barrel back will only fit into a Dye UL I tip. Accuracy DYE versified. The new DYE UL I Barrel Insert System has reset the standard for accuracy and quality. The UL I is THE upgrade for paintball markers and offers