Checkline K-300-50 Analog Dial Thickness Gauge, Range 50mm, Depth Of Jaw 300mm. Measuring Range: 0 - 50 mm / 0 - 2.0 inch, Jaw Depth: 300 mm / 11.8 inch, Resolution: 0.1 mm / 0.01 inch. The K-300-50 thickness gauge is an easy-to-read analog display along with high accuracy. 5 different feelers are available, they are listed below. The K-300-50 is ideal for determining the thickness of leather, textiles, cardboard, felt, rubber, sheet metal, foil, plywood, plastic, etc.