Ultimate Arms Gear 14.5mm-1 LH Pistol Handgun Black Phosphate Coated Steel Thread Protector Cap Made in The USA For M14.5x1 Left Hand TPI Thread Pattern Glock 10mm .40 Cal 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!