Mini-Rocket: Mini Pipe / Diameter Caliper and Ruler - Fractional - 5 Pack Mini pipe diameter caliper. Measures up to 6" diameter and pipe sizes to 5" diameter Unique design with a swing arm that extends into a 7" ruler Product comes in a package of 5 individual units Conversion chart for outside diameter to inside diameter printed on caliper Made of .030" thick white vinyl and clear coated for durable protection