Don't know your ring size? Purchase this reusable plastic ring sizer—very simple to use!
Instructions [included on the paper envelope]: "The Multisizer works like a belt. Simply push the end through the buckle to form a ring shape. Slip the Multisizer onto your finger. Adjust to give a comfortable fit, checking that it just slips back over the knuckle. When best fit is achieved, read off size indicated by the arrow!"