The nerf modulus system lets kids build their own blaster for each mission or battle attach any of the modulus gear accessories to upgrade and customise the nerf modulus blaster sold separately with the full nerf modulus system over 1000 different combinations are possible blaster accessories and upgrade kits each sold separately upgrade the nerf modulus blaster sold separately part of the nerf modulus system customise for any battle or mission one supplied for indoor and outdoo