CT-492 Igniter Erosion Gauge (Formerly CT-468) A special tool designed specifically to measure the erosion-wear of Champion AA series igniters. Calibrated in colored scale segments to determine the extent of erosion of the undercut area of the steel shell, not easily visible to the eye. Measuring tips shaped to reach into the undercut, true-wear area. Instructions for use included in special plastic box. Size: 61/4 in. X 41/4 in. X 11/2 in./15.8cm X 10.7cm X 3.8cm Shipping weight: 10 oz./238g