Delta V PRG-1 Drop In Pistol Trigger. The PRG-1 will work with any Glock style Gen 3 or Gen 4 9mm/40 S&W/357 Sig double stack Glock or Glock style frame and pistol. The PRG-1 trigger allows a massive increase in cyclic rate by firing one round when the trigger is pulled and a second round when the trigger is released. This is the only Glock pull-release trigger on the market with an ATF issued determination letter which expressly establishes the PRG-1 as NON NFA The PRG-1 is not recommended for use in duty/carry pistols. Enjoy the PRG-1 thrill on the range Specifications for Delta V PRG-1 Drop-In Pistol Trigger: Manufacturer: Delta V Gun Model: Glock 19 Gen 3 Glock 19 Gen 4 Gun Make: Glock Last Chance: Yes Caliber: .357 SIG 9mm Luger .40 S&W Gun Type: Pistol Package Contents: Delta V PRG-1 Drop-In Pistol Trigger PRG-1 Safety Plunger Red Back Plate What firearm models does the manufacturer say Delta V PRG-1 Drop-In Pistol Trigger is compatible with? The manufacturer says that Delta V PRG-1 Drop-In Pistol Trigger is compatible with Glock 19 Gen 3 Glock 19 Gen 4Delta V G-1100-A: PRG-1 Drop In Pistol Trigger