This Kriss-USA Mag-Ex Kit 2 is a magazines extension kit for people who already have full size GLOCK 17 magazines and wish to make them a full 40 round capacity. The magazine pairs perfectly with your Kriss-USA Vector chambered in the same caliber. This extension will provide you with extra capacity and comes with everything necessary to convert your existing factory magazines. Specifications & Features: Mag-Ex2 Factory Kit Fits GLOCK Factory Magazines Constructed from durable/lightweight composite polymer Adds Capacity to Factory Magazine Reliable Feeding Kriss Vector Aesthetics Converts Total capacity to 40 Rounds 9mm /10mm / 45ACP Luger Includes: Extended Baseplate Outer Sleeve Extended Spring