The Stopwatch Specialists We specialise in the design and manufacture of stopwatches to our own specification. If you are looking for a stopwatch you need look no further than AST. For a stopwatch to be suitable for serious swimming timing and coaching, it needs to be able to time in minutes, seconds and 1/100th second. Ideally it also needs to be waterproof*. A memory function is preferable so that you can recall your lap times and cumulative lap times by using the memory recall function. The running time shown on the stopwatch display should be the cumulative lap running time. Other useful stopwatch functions for coaching include stroke rate, and pacer. The stroke rate is used to calculate the "strokes per minute" of a swimmer. A pacer can be used to set a required stroke rate to be maintained.