Know what’s happening at every entrance to your home with the iSmartAlarm Contact Sensor Door & Window Alarm. This compact gadget attaches to both sides of your door or window, notifying you instantly if it opens. In fact, this iSmartAlarm is great for cabinets. That means you can use the Contact Sensor to monitor if your child opens a cabinet with cleaning supplies. A completely wireless device, this sensor uses batteries to stay powered up. Plus, it’s easy to install these sensors with the included double-sided tape. What’s more, this window sensor requires the CubeOne central hub to communicate with. It’ll alert the hub if any of these sensors detect a breach in your settings, setting off the CubeOne 110-decibel alarm.