The ETS pistol 17 round mag is constructed of an extreme impact resistance advanced polymer with superior heat, cold and UV resistance, translucent body, and is creep resistant which means the feed lips and body won't spread when being stored long term even when fully loaded. This mag features a base plate that is interchangeable with ETS line of 9mm double stack magazines. It has easy disassembly with ETS's specially designed base plate and is also designed to be compatible with Glock extensions. The ergonomically designed floor plate makes it easy to grab from mag pouches. NOTE: This mag is not compatible with the S&W M&P Shield.