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 4 in/0 mm to 100 mm Joint Type / Spring Maximum Measurement / 100 mm, 4 in Maximum Measurement - Inch / 4 in Maximum Measurement - mm / 100 mm Minimum Measurement - Inch / 0 in Minimum Measurement - mm / 0 mm Nut Type / Solid Tip Type / Solid Points Caliper Material / Steel Leg Style / Flat