VFC FI MK2 G17 Aluminum RMR Slide & Barrel Set for Umarex / VFC Glock 17 G17 Gen3 GBB Pistol Series ( Licensed by FI ) Masks prevent the bolt from locking

prevent the bolt from locking back on an empty magazine thus allowing you to simulate shooting without ammo

Photos for reference only

FCC Forged Lower Receiver (blank marking)

Infra Red Patch - Multicam South Korea Flag

VFC FI MK2 G17 Aluminum RMR Slide & Barrel Set for Umarex / VFC Glock 17 G17 Gen3 GBB Pistol Series ( Licensed by FI ) Masks prevent the bolt from lockingLicensed by FI ( Fowler Industries ) For AIRSOFT Use ONLY! For Umarex VFC Glock 17 Gen3 GBB Pistol Series Product content: Aluminum Alloy FI MK2 G17 Type RMR Slide x1 Aluminum Alloy FI BLK G17 Type Outer Barrel x1 Aluminum Alloy Optical Fiber Front Sight x1 Aluminum Alloy Optical Rear Sight x1 Aluminum Alloy RMR Mount Dummy Base Cover x1 Steel RMR Adapt Pad x1 Steel Extractor x1 RMR Lock Screw x3 (1 Backup) RMR Lock Screw O ring x3 (1 Backup) RMR