In the market of expanded capacity magazines for Glock handguns, most manufacturers focus on 9mm options at the expense of other calibers that continue to be popular with today's handgun owners. One of those often-forgotten calibers is the .40 S&W, and these Glock 22/23/27 polymer magazines offer expanded options for more mags, as well as an increased capacity option that holds up to 27 rounds. Each Glock 22/23/27 polymer magazine is built for use with the .40 S&W cartridge, and the magazine body is constructed using DuPont's proprietary Zytel polymer, which has been proven to be durable and long-lasting. Constant spring pressure is provided by a heat-treated chrome-s Mfg: Pro Mag