Our rings are banded into small, medium or large to give you an idea of the size and fit. Further size information can be found in the details section when you click on the ring. Even as an adult I still love mood rings and they are one of my best sellers at fetes and fairs. Children love them. They are made of a thermochromic liquid crystal that can respond to changes in temperature, producing different colours at different temperatures. Each mood ring comes with a little card showing the different moods of the colours.