Boys can build their own blaster for each mission or battle with the Nerf modulus ion fire blaster from Hasbro. Customise the blaster with the barrel extension and dart storage. Slide the dart holders onto the blaster's tactical rails to keep darts within reach for quick reloading. Heading into battle? customise with the barrel extension. On a covert mission? remove the extension to create a stealth-sized blaster. The Nerf Modulus ion fire blaster fires one dart at a time and comes with four darts. Expand the customising options with Nerf Modulus upgrade kits (each sold separately); with the full Nerf Modulus system, over 1000 different combinations are possible numbers.