Agile-shop V3 Best Lap Timer Set of Receiver Beacon Infrared Ultrared + Transmitter Stopwatch A great lap timer at a fraction of the cost of other on the market. Designed to be reliable and durable including shock proof. Efficient design means you can run multiple track days with a pair of batteries. Great for track days or sporting events! Easy to use - 30 second setup time. Up to 50 Hours Battery life for the timer and 5 hours for the beacon. Up to 15M signal distance (48 Feet). The time tolerance of this device is 0.0035 seconds for each lap; Max Lap time and Max total time: 99 minutes 59 seconds. This device is designed for track day and trainers; It has all basic function that is required for track day. The signal receiver is built in the timer, make sure the receiver is exposed to the "signal wall" created by the transmitter; When there is continuous signal, only the first signal will be counted.