Smart Skimmer Security uses the uniquely-designed contactless optical sensor to secure the skimmer. No moving parts that will fail. Magnetically coupled sensor makes it super easy to install and to adjust to the desired level on the collection cup. No holes on the collection cup are needed for installation. Maintenance is also as simple as you can imagine. As the level in the cup goes too high, Smart Skimmer Security will shut down the skimmer immediately to prevent your skimmer from overflow.