Tapco(R) +5 Magazine Extension is designed for compatible Glock 17 and Glock 19 magazines. The extended base provides an additional 5 rounds of magazine capacity and features durable aluminum construction with a black finish. It is designed as a replacement magazine base component for compatible Glock magazines.Key Features Designed for compatible Glock 17 and Glock 19 magazines Adds 5 rounds of magazine capacity Designed for 9mm applications Aluminum construction Extended magazine base design Black finishTapco(R) manufactures firearm accessories components and maintenance products for a variety of firearm platforms. The brand offers products designed around practical compatibility and durable construction. Tapco accessories include magazine-related components firearm parts and supporting equipment.