Learning Resources Simple Stopwatch (Set of 6). Timing practice even youngsters can master! These simple stopwatches feature just three easy-to-use simple buttons (green for go, red for stop and yellow for clear) and an easy-to read large digital display that shows minutes, seconds and hundredths of a second. These colourful simple stopwatches measures 7cm H. Each stopwatch requires one 1.5V button-cell battery (included). Colours may vary. Set of 6. Suitable for ages 5+