Circuit training with intervals is a vital part of any exercise and endurance program. The Circuit Trainer regulates exercise and rest ratios with an audible sound and digital display. Using programmable time periods, the Circuit Trainer eliminates gaps between training and efficiently moves athletes through their workout. Users can focus their attention on the workout at hand instead of the clock. Set each time period to count down from 5 seconds to 30 minutes, and program up to 99 different rest/exercise cycles. The Circuit Trainer includes a halfway alert for lateral exercises, and an adjustable volume that can be heard up to 100 yards away. A versatile piece of technical fitness equipment, the Circuit Trainer is appropriate for all types of sports including swimming, soccer, basketball, and football. AC adapter included, or uses two 9-volt batteries (not included).