This goes beyond just a silicone ring. It offers a stylish protection for your special ring when you are working out, rock climbing, moving, biking ,cooking or just any heavy duty work that could cause blemishes to your ring. Also instead of taking your ring off all the time and possibly misplacing it. This you can slip on and forget about it.
Silicone rings are expandable. So if you're unsure, it's ok to get something a little smaller and loop it around your ring first. But the most accurate way would be to take a string and loop it around your finger like the picture to the right. Mark the two ends that meet and measure what size your finger size is needed.