Accelerator paste MADBULL Sniper Hopup Bucking is manufactured with soft material comprising silicone rubber and to allow maximum adjustment and improve the overall performance of sniper rifle. Specially designed to seal the compressed air and prevent double feeding bbs. This product includes two rubbers compatible with rifles Echo1 M28 and VSR-10. Sniper gum Accelerator MADBULL take your rifle to another level of accuracy!