Interval workouts have become an important part of any solid training regimen. The Top Contender Interval Timer provides many options to fit your individual training requirements. Round lengths can be set to 2, 3, or 4 minutes. Rest periods can be set to 15, 30, 45, or 60 seconds. Intervals can be set to 15, 30, 45, 60 seconds, or no interval. To eliminate confusion, different sounds indicate the beginning or end of the round and the interval.