Checkline DMD-820-1 [DMD-820-1-H] Digital Thickness Gauge, Range 0 - 1 in (0 - 25 mm), Jaw Depth 200 mm, Feeler H (30 mm) For Foams And Insulating Materials. 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.