The main goal is to make sure people are using their pumps to get the maximum results. If you asked 100 people to say stop after 3 minutes, they would all say a different amount of time, meaning people are either under- or over-pumping.
The green lights indicate the 3 minutes you should be on the extractor and the red lights indicate the time you should be off the extractor. This can be repeated 3 times to follow the manufacturer's recommendations on how to use the extractor. Most people don't wear a watch (or glasses!) in the shower so the lights and beeps make it visual and audible to indicate the time needed when using the extractor. It comes with 2 size suction cups, one to attach to the extractors and a larger one if the user prefers it on a shower screen or tiles.
