Timers are compatible with U.S. based, 115-volt outlets. For customers outside the U.S., an electrical converter must be used to ensure proper operation. An amazing audio and visual gym timer that is perfect for every size workout area. Easily sets for 2 or 3 minute workout periods. Rest period can be adjusted from 30 seconds or 1 minute time length with the flip of a switch. Three way adjustable ring bell can be heard in any size gym. Complete with 30 second end of round warning whistle. The capped lighting system visually indicates where the round is at all times - green for workout, yellow for 30 seconds remaining and red for rest period. Complete 1-year warranty. Size: 11" L x 4" W x 8" H.