Checkline DM-820 [DM-820-H] Analog Metric Dial Thickness Gauge, Range 0 - 25 mm, Jaw Depth 200 mm, Feeler H (30 mm) For Foams And Insulating Materials. The analog dial thickness gauge DM-820 determines the thickness of various materials, like leather, textiles, cardboard, felt, rubber, sheet metal, foil, plywood, plastic, etc. This thickness gauge is self closing and guarantees high accuracy and resolution.