Ultimate Arms Gear 13.5mm-1 LH Pistol Handgun Black Phosphate Coated Steel Thread Protector Cap Made in The USA For M13.5-1 TPI Thread Pattern Glock 9mm Designed to Protect Barrel Threads when not using a Muzzle Brake or and Device. Machined from Black Phosphate Coated Steel and Knurled for a Positive Grip to Assist in Installation and Removal. Dimensions: 0.69" Diameter x 0.46" Long. Weight: 0.4oz. Small & Compact Highly Effective. Designed in and Made in USA with USA Steel!