This ring embraces a color changing mood stone! The cabochon is set in nickel & lead-free bezel setting. Mood rings change color in response to temperature because they contain thermochromic liquid crystals. Ring bezel is 7/16 in diameter. That means it's almost 1/2". Ring band is less than a 1/4" in width. It's adjustable, lead free, and nickel free. The ring starts at about a size 6 1/2 - 7 and can go up to a size 9 comfortably.