Feeler Gage is made from 1/2" wide spring steel stock, close grain C1095 high carbon steel. Used in manufacturing, tool and die, and maintenance operations wherever setting close spacing or checking extremely tight tolerances is required. Hardened and tempered to RC 48-62. Thicknesses are clearly etched every 6" in decimal and metric. Also available in bulk quantities. Other sizes or thicknesses are available on special order.