Checkline DMD-820-1 [DMD-820-1-A] Digital Thickness Gauge, Range 0 - 1 in (0 - 25 mm), Jaw Depth 200 mm, Feeler A (6 Mm) For Rigid Leather, Glass, Sheet Metal. hickness gauge to determine the thickness of leather, textiles, cardboard, felt, rubber, sheet metal, foil, plywood, plastic, etc. Self closing thickness gauge with high accuracy and resolution.