The Apex grade thread protector is expertly designed to provide superior protection for threaded pistol barrels, ensuring long-lasting durability and reliability. Precision-machined for a secure fit, it helps prevent damage to barrel threads while maintaining a sleek and functional design. Each protector comes with a pre-installed O-ring, offering a secure hold and added stability. This high-quality accessory is included with Apex's line of threaded barrels, making it an essential component for shooters who demand peak performance and longevity from their firearms. Screws on to the end of your 9mm threaded barrel to protect the threads from damage, ensuring longevity Unique offset pentagon pattern provides a distinctive look Captured O-ring pre-installed and remains in place in the thread protector when removed, providing a secure and easy-to-use sealing solution for barrel threads 9mm options for pistol barrels featuring 1/2-28 threads (right handed), offering compatibility with popular suppressors and muzzle devices