The Tippmann Hopper Bolt. It never hurts to have extras! Fits most guns.
This product is used in the following guns: 98 Custom Non-ACT, 98 Custom ACT, 98 Custom Response ACT, 98 Custom E-Grip Electronic ACT, 98 Custom Pro ACT, 98 Custom Pro Response ACT, 98 Custom Pro E-Grip Electronic ACT, Alpha Black Basic, Alpha Black Tactical, Alpha Black E-Grip Electronic, Alpha Black Tactical E-Grip Electronic, Bravo One Basic, 98 Ultra Basic Non-ACT Platinum Series, 98 Custom ACT Platinum Series, 98 Custom Pro ACT Platinum Series, Pro Carbine, Model 98, Carver One, Project Salvo.
The Tippmann Part Number for this product is PL-42C.