This Standard Products manufactured 15 round metal constructed magazine assembly is for the U.S. military model M1 Carbine semi-auto rifle and is in very good condition with light wear. It is a type I magazine which does not have a ridge in the floorplate. This magazine does not have a hole in the rear bottom of the body; nor does it have one in the floorplate. A circle encloses the SL marking. There is an M scratched on both sides of the magazine. You can see it in the photos. Standard Products was a wartime manufacturer of these magazines. (file photos)