Works like a belt. Turn and push end through to form ring shape. Slip onto finger. Adjust to a comfortable fit that slips over knuckles without difficulty. Read the indicated size after determining the best fit.
Please keep in mind the Gauge measures 5mm wide. If the ring you are looking to order is wider we recommend you do not pull the gauge tight as this will make a wider ring feel too small. The wider the band the tighter it will feel on your hand.