Size:8" ISOM 360⁰ | Style:HiRes This plastic goniometer is constructed with clear plastic permitting the observation of joint's axis of motion and range of motion. The 360 degree head has three scales calibrated for use with the ISOM (international standards of measurement) system. White background behind the gradations, numbers and text assures high contrast for added readability and resolution. Scale reads 1 degree increments.