Pocket Rocket: Pipe / Diameter Caliper and Ruler - Fractional - 3 Pack - White Styrene Pipe diameter caliper. Measures pipe sizes up to 16 inches in diameter Unique design with a swing arm that extends into a 14 inch ruler Product comes in a package of 3 individual units Conversion chart for outside to inside diameter, and fractional to decimal, printed on caliper Made of .040 thick white styrene