Double Action - Self centering for quick checking of inside measurements. Uniform contact pressure. Plunger or gage expands in hole to be measured, is locked in place and gage is removed from the hole. Final hole size is obtained by measuring over contacts with a micrometer. Constant spring tension for uniform feel. Rigid handle with self centering feature. Satin chrome finished. Contact Points are of hardened tool steel and precision ground on the end measuring radius.
