Its human powered and so darn fun to play with as it features micro-precision flowers that turn when the outer rim is spun. The Rachel ring is made from high quality 316L sandblasted stainless steel. It's highly durable and resistant to tarnishing, fading, scratching and rusting. It will not bend or break. It is known to be hypoallergenic for those with metal allergies. This ring is new in its bag and the metal color is silver. The ring is a size 7.