[EASILY DETERMINE RANGE OF MOTION] Goniometer physical therapy primary purpose is to assist in physical therapy by determining the range of motion of a joint. It's an to gauge recovery after surgery or physical therapy. [AN ESSENTIAL TOOL FOR TREATMENT] Angle rule goniometer is an essential tool for anyone who works in or is going through physical therapy, sports therapy, or a rehab program following surgery or an accident. [360 degrees of coverage in 1-degree increment]6 / 8 / 12 inch large goniometer, Various scales can offer a variety of readings. [CLEAR READING] The numbers and lines on the occupational therapy tool kit are clear and accurate. You can easily read these numbers to plays a practical role. size:15cm,20cm,30cm Material:plastic colour:Transparent Package Contents: 6 x Goniometer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.