If you ride a motorcycle (or just like to look like you do) then this ring belongs on your hand ASAP. Would go great with a leather jacket. Note that it is a relatively impure silver.
Ring size 10
Unless otherwise indicated, rings should be resizable by your local jeweler for a very modest cost (usually $20 or less, unless you're dramatically enlarging a gold ring). You can find your ring size with this online tool (http://findmyringsize.com/) or get a free ring sizer here (https://www.bluenile.com/