Faster and easier than ever before, HKS magazine speedloaders quickly load single or double stack magazines. It's that simple! The magazine slips into the loader and is held in by hand. Depress thumb lever and load. That's it! This speedloader is made for Glock 17,19,22,23,26,27,33,34,35 and 39. It is also compatible with the H&K USP, as well as the S&W Sigma 9mm and 40 cal.