Helps the therapist perform accurate and precise finger range of motion measurements. Scale is in two degree increments for improved reliability. Ruler is in both inches and centimeters. The long arm is 9.5cm (3¾") long and it clears the wrist for accurate placement. If a shorter arm is desired, the goniometer can be trimmed to meet measuring preferences. Composite motion is measured easily because the goniometer's short arm is only 2cm (¾") long, allowing precise measurement of DIP range of motion. Measuring degrees of hyperextension is simple - no repositioning is necessary. The goniometer easily provides readings ranging from 30º of hyperextension to 120º of flexion. Loose fitting hinge lies on the joint without guidance.