Features Inside spring and firm joint calipers have two symmetrical legs that come together at a joint to form a jaw. The jaws are adjusted and the outward-facing contact points on the ends of the legs and the distance between the contact points is measured. They are commonly used to take indirect inside measurements in metalworking, machining, and woodworking applications. Range / 0 in to 6 in/0 mm to 150 mm Joint Type / Spring Maximum Measurement / 150 mm, 6 in Maximum Measurement - Inch / 6 in Maximum Measurement - mm / 150 mm Minimum Measurement - Inch / 0 in Minimum Measurement - mm / 0 mm Nut Type / Solid Tip Type / Solid Points Caliper Material / Steel Leg Style / Flat