Easy to install and use - Swimming pool/door/gate alarm with remote control. Multifunction - Magnetic Contact Door Alarm/Door Bell/Swimming Pool Door Alarm/Refrigerator Door Alarm/Door Break Alarm Remote synchronization - Multiple remote sensors can be synchronized. Magnetic Shutters - Alarms when the elderly and children with dementia open windows or interior doors. Avoid ANY accidents - Keep children out of closets, above ground pools, supervised walks, sleepers, the elderly. Food : 2 AAA batteries (not included) Note: The data is all measured manually, please allow 1-3 error cm, due to the difference in light and display, there will be a certain color difference, the actual object received shall prevail.