APS shotgun rail attachment uses green gas/ propane or co2 for a close quarters quick shot of 12-15 bbs all at once! You can even attach this to the rail of a pistol or rifle. You just fill it with gas, then put the wad in and fill with bbs and then put a paper cap on to hold them in. It has a firing pin just like a real shotgun shell. You just slide it into the launcher and load it into place and push the trigger and boom! This is a really cool design by APS. Comes with the two shells shown, the rail launcher, belt clip, and 100 wads and caps. This is a really good price for this cool airsoft inovation. The shells are mostly metal except the red part which is plastic just like a real shotgun shell. This wide spread of 12-15 bbs at one will give you an almost guaranteed kill in close quarters. Im selling because I don't really use it that much I mostly play on larger fields but it has come in handy a time or two in buildings and I hit 3 people at once with one shot. Only trades are for gas guns 60$ shipped