For the ultimate in high-performance sports action, it's Nerf or Nothing'! Build and customize for any mission or battle with the Nerf Modulus system of blasters, upgrade kits, gear, accessories, and darts. The Nerf Modulus Ghost Ops Chrono Barrel upgrade that keeps track of darts as they are fired from the Nerf Modulus Ghost Ops Evader blaster! (Blaster sold separately.) The Nerf Modulus Ghost Ops Chrono Barrel upgrade counts darts as battlers fire them from their Nerf Modulus Ghost Ops Evader blaster. Select to program the barrel to see how many darts are fired during an entire battle or the number of darts remaining in the blaster. Built-in memory also remembers the last number of darts set in the count-down mode. Players can keep track of their darts so that they're ready to reload and stay in the battle! (Blaster sold separately.) The Round Count Barrel also measures the velocity of the darts being fired in either feet or meters per second. It attaches to the front of the Nerf Modulus Ghost Ops Evader blaster. This Nerf Modulus Ghost Ops upgrade also comes with 6 darts. The barrel and is s also compatible with other Nerf Modulus blasters. (Blasters each sold separately.) The Nerf Modulus Reflective Chrono Barrel upgrade kit is part of the Ghost Ops series that also includes the Evader blaster and the Reflective Targeting Kit. With the entire Modulus system, more than 1000 combinations are possible! (Blasters, upgrade kits, and accessories each sold separately).