During Count-Down-Timer, you can give a time span, after its' run a ton signal is triggered. With Count-Up-Timer, it is similar like a stop watch identifying an elapsed time span. In addition to this, it can also activate & optical alarm for the count-down-timer. The background light is illuminated in last 60 sec.of the green timer time, till 30 sec. it is blue & till 10 sec. it is red. During the one minute alarm tone, automatic colour change takes place.