2x O-rings for Nerf Elite Blasters O-rings are essential in maintaining the air seal in your blaster. Over time, they can wear out and deteriorate, allowing air to escape the plunger and dramatically reducing range and muzzle velocity. Occasionally replacing the o-rings in your blaster will help keep it consistent in range and power. This set of 2 O-rings include one large ring and one small ring that will fit the following Elite blasters. Compatible With: Retaliator, Elite Alpha Trooper, Rampage, Strongarm, and Firestrike Blaster not included.