You have to take it off your finger to use it, but it really works. Sundial ring is based on one Eleanor of Aquitaine gave to her second husband, King Henry II, around 1152. Follow the simple instructions included to shine a bead of sunlight through the hole and onto the inside of the ring, then read the time there. Stainless steel with brushed nickel finish, 3/8" wide, sizes 6, 8, 10, or 12. Wear on a finger or chain (sold separately).