Glock Gen Factory Thread Protector Features The Glock Gen Factory Thread Protector is manufactured specifically to match the M16x1LH thread pitch found on threaded barrels for the Glock 21 Gen 4 a .45 ACP pistol. Because it is a genuine factory component rather than an aftermarket substitute it threads on with the same precise fit that Glock s own barrels are machined to reducing the chance of cross-threading or a loose fit over time. Keeping the protector installed when no suppressor or compensator is attached shields the exposed threads from dirt moisture and impact damage that can otherwise degrade thread quality. This small detail matters for any shooter who plans to add a muzzle device down the road and wants the threads ready to go. Finished in black to match the factory barrel and slide the thread protector maintains the pistol s clean factory appearance when no muzzle device is mounted. It ships as a simple single-piece package that installs and removes by hand without any special tools. For Glock 21 Gen 4 owners who already run a threaded barrel having a correct factory thread protector on hand is a low-cost way to preserve resale value and thread integrity. The Glock Gen Factory Thread Protector is a straightforward purpose-built accessory for any Glock 21 Gen 4 shooter who wants genuine factory parts on their threaded pistol. Glock Gen Factory Thread Protector Specifications Manufacturer: Glock Model: Gen Factory Thread Protector Type: Thread Protector Compatible Hosts: Glock 21 Gen 4 Thread Pitch: M16x1LH Color: Black Quantity: 1 Available At: GrabAGun