Direct reading markings are permanetly laser etched onto stainless steel body
Small enough to carry in your pocket
Works with any .30 caliber barrel
Muzzle wear gage for any .30 caliber rifle barrel. Measures from .300 to .303 diameter very simply and quickly. 100% made in USA from alloy steel with direct reading permanently laser etched markings. Typically, when it gets up to .303" diameter its pretty well worn out, less than that depends on how picky you are. Gage reads .30 on the handle and segments indicate last two digits, for example .30 + 15 = .3015 diameter.