Enhanced versions of the USP, the HK USP Tactical V1 models are designed for users who need the features found on the HK Mark 23, but in a more compact pistol. Both pistols approach the precision found on the Mark 23 by adding an extended threaded barrel with a rubber O-ring, adjustable trigger, and adjustable target-type sights. The .45 ACP model of the USP Tactical V1 is constructed on the USP45 frame. The 9 mm and .40 S&W Tactical models are built on the USP 9mm/40 caliber frame. The 9 mm variant, known as the USP9 SD, has a slightly different set of features. 9mm does not included o-ring barrel, match trigger, and adjustable trigger stop. This HK firearm includes two 10rd magazines.