Nerf Triad

The blaster is able to hold up to three darts at a time in its three triangularly placed barrels; what is unique about this blaster is that it "knows" which barrel is loaded and ready to fire. The blaster does not feature a tactical rail due to its small size. A small set of iron sights is located on top of the blaster.

The Triad features an intelligent air restrictor system like the Rough Cut 2x4 and the Crossfire Bow. The blaster fires a single dart by closing off the hole to the next chamber when a dart is inserted. This way, only the first chamber with a dart in it gets air flowing through it. When all three barrels are loaded, the blaster will fire clockwise starting from the bottom barrel.

Source: http://nerf.wikia.com/wiki/Triad_EX-3