Feeler Gage is made from 1/2" wide spring steel stock, close grain C1095 high carbon steel. Used in manufacturing, tool & 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.