The AKS-74 ("S" – Skladnoy [Folding]), is a variant of the AK-74 equipped with a side-folding metal shoulder stock, designed primarily for use with air assault infantry and developed alongside the basic AK-74. Unlike the AKMS's somewhat fragile underfolding stock (modeled after the MP 40 submachine gun stock), the AKS-74 stock is fabricated from stamped sheet metal struts, machine pressed into a "U" shape and assembled by punch fit and welding. The stock has a triangular shape; it lacks the folding shoulder pad found on the AKMS stock and is folded to the left side of the receiver. The hinged stock is securely locked in its extended position by a spring-loaded button catch located at the rear of the receiver. When folded, the stock is held closed by a spring-loaded capture hook situated on the left side at the front of the receiver housing. A rear-mounted sling swivel is also provided on the right side at the beginning of the stock frame.