Candles have a built-in timer to stay lit for 5 hours, then off for 19 hours, repeating the cycle automatically each day. Candles are dipped in ivory wax and have a realistic, LED flicker-like flame. Each candle requires 2 AA batteries (not included). Small size measures 3" high by 3" wide. Medium size measures 4" high by 3" wide. Large size measures 6" high by 4" wide.