This plastic goniometer permits observation of a joint's axis of motion and its range of motion. The primary purpose of this device is to assist in physical therapy by determining range of motion of a joint as well as evaluating and gauging recovery after surgery or physical therapy. The 360░ head permits reversable readings, allowing for the device to be flipped so the display is read more easily. The digital display reads continuously as arms are adjusted. This is an essential tool for treatment, rehab and surgical recovery and evaluation. Suitable for home use as well as multi-user environments. The arms are 10?. This goniometer lets you measure joint limits and range-of-motion as well as check extension, flexion, abduction, adduction and rotation. The arms have a linear scale in both inches and centimeters. They also will remain at the last measurement position until reset. The 360░ angle scale reads .05░ increments. The plastic of the goniometer allows the device to be placed directly on a joint or limb for easy observation. This Goniometer is a Baseline product, which means it?s a trusted name in measurement and evaluation instruments. Baseline products have been used by Medical Professionals, Therapists, Doctors and Rehab Clinics all over the world since 1974. If you have ever received therapy after an injury, you have probably had your progress tested and measured with a Baseline measurement instrument.