The EM8660 wireless door/ window contact is suited for use with the Eminent EM8610/EM8605 Alarm System. The magnetic contact is suitable for doors and windows. The alarm is activated once a closed window or door is opened. The EM8660 works wireless and is powered by 1 AA Battery. Therefore easy to install on every door or window. The EM8660 notifies you via the alarm system when the batteries need to be replaced.