Timers are compatible with U.S. based, 110-volt outlets. For customers outside the U.S., an electrical converter must be used to ensure proper operation. The ideal digital countdown timer for any sized gym or individual workouts. This is the most versatile gym training timer available for the price. Round lengths can be easily set from 30 seconds to 9 minutes. Rest time can be adjusted from 30 seconds to 5 minutes. Use for all boxing, MMA, grappling, wrestling and combat training, as well as all conditioning and cardio workouts. Extra large 2" digital display can be seen in any size gym. Complete with accompanying lights to show Work, Rest or 30 Seconds remaining in the round. Also includes a high, medium and low bell volume control to adjust sound for any size training area. Complete 1-year warranty. Size: 8" L x 3" W x 8" H.