My school asked for a synonym and antonym for stopwatch I have a synonym but I cant find any antonyms

A timer

Explanation:

Stop watches go forward and Mark a certain time whilst a timer stops at a specific time. You can determine when a timer can stop but can’t with a stop watch.

Hi!

Explanation:

Stopwatch: Digital clock is the synonym and antonym is not running

but it is sometime nessary to hit key points or subjects   but is sometimes to much reveiw if there was a way to slim down the redone work it would improve for every body.