This wireless motion detector by Ideal Security® monitors driveways, gates, sheds, walkways, and swimming pools. It can also be used to monitor front or back doors at small businesses, or supervise children to keep them safe. The motion sensor works in both light and darkness. To scare off intruders, choose the high-decibel alarm. In situations where movement must be restricted, this alarm set can provide a gentle chime indication to warn others. Use the lights-only mode to silently keep an eye on movement in areas of your home, shop, or place of work. Must be linked to SK602 series alert.