Hold the trigger down and they keep firing! It shoots 6mm soft air pellets. It requires 4 AA (not included) Each gun comes packed with 100 pellets in a beautiful color box. Don't forget to order extra ammo. These shoot farther and faster than most full auto airsoft guns. You will not be disappointed with the quality or the durability. This gun is made of ABS plastic. To fire the gun all you do is load the ammo in the top (under the front site) then put the 4 double a batteries in the handle, push the safety button and hold down the trigger. You can fire this gun as a semi auto if you push the trigger for one second. This is a fully automatic machine gun. This gun is made by UHC - the leader in airsoft gun.