Easy ring sizer and reusable. This ring sizer saves so much time by helping to avoid unnecessary resizing due to inaccurate ring sizing. This ring sizer is easy to use. Simply try the sizer on and adjust the gauge to where the ring feels the most comfortable on the finger in which you would like to wear your custom-made ring. The plastic finger gauge measures U.S. sizes 1–17 in half-size increments; the increments are clearly marked.