XTech Tactical(R) MTX Magazine Extension is designed for compatible H&K VP9 9mm magazines. The extension increases a compatible magazine configuration to a 21-round capacity and features a black finish. It provides an extended-capacity configuration while maintaining compatibility with the VP9 platform.Key Features Designed for compatible H&K VP9 magazines Designed for 9mm ammunition Provides a 21-round magazine configuration Magazine extension design Black finishXTech Tactical(R) manufactures magazines and firearm accessories with an emphasis on durability reliability and functional design. The company develops components for a variety of popular firearm platforms and uses purpose-selected materials and manufacturing processes. XTech Tactical products are designed and manufactured with attention to consistent fit and dependable operation.