This transparent plastic goniometer permits observation of a joint's axis of motion and its range of motion. The 180° head has three scales calibrated to be used with the ISOM (International Standards of Measurement, STFR) system. The 180° angle scale reads 1° increments. The arms are 6 inches long. The arms have a linear scale in both inches and centimeters. They also will remain at the last measurement position until reset.