This type of magazine is one of the first magazine designs used with the AK. Made by several countries, most notably Russia and East Germany, these magazine are usually sought after person(s) looking to construct a exact replica of the original AK design. The slabside design was prone to not function at all if the magazine became dented. It was then replaced by the stronger “Ribbed” design. Don't let this deter you from purchasing one though; the magazine is just as reliable as the ribbed AK magazines.