What's a Sticky Holster? Since our inception, we have developed these holsters into a modular system, where you can use it IWB, in the pocket, on your ankle using our ankle rig, and for police officers, on their tactical/armored vest, etc. They don't come with clips or loops to secure it in place, as the outer "sticky" skin adheres to your waistband, undergarments, and/or your skin. The outside skin is a super non-slip material that, with a little pressure, adheres to just about anything. That outer material combined with the inner closed-cell foam and the inner liner keeps your pistol and the holster securely in place. However, when you pull the gun, the outer layer grabs the inside of your pocket. Our modular products use the same "Sticky" material against itself to hold the holster and gun in place. In addition, with use and body heat, your Sticky Holster will conform to your particular gun, making a custom fit. The MD-4 Medium fits Single Stack Sub-compact Medium Autos up to 3.6" barrel, such as Springfield XDs(3.3), Glock 43, S&W Shield, and other makes/models with similar frame size. Ambidextrous fit for right and left-handed users. Fits the Following Guns: - Model Name Caliber Barrel- Bersa Thunder 9 UC 9MM 3.25- Bersa Thunder Pro 40 UC 40 S&W 3.25- Bersa Thunder Pro 45 UC 45 S&W 3.6- Bersa Thunder Pro 9 UC 9mm 3.25- Walther PPS All 3.2- Kahr CW 45 45ACP 3.6- Kahr CW 40 40S&W 3.6- Kahr CW 9 9MM 3.6- Kahr P9 9mm 3.6- Glock 43 9mm 3.39- Sig Sauer P239 9mm,.357 SIG, 40 S&W 3.6- Smith and Wesson Shield 9mm, 40 cal 3.1- Smith and Wesson Shield 45 ACP 3.3- Springfield Armory EMP- Springfield Armory XD-S 9mm, 40 cal, 45ACP 3.3- Springfield XDS 3.3- Walther CCP ALL- Walther PK380 380ACP- Walther P22 (3.42 in barrel) 22LR - Walther PPS M2 9mm 3.18.