Sorry I meant to ask if they are wireless? They are fitted on windows frame as vibration sensors, had an attempted break in and their usual route of entry is through the windows. I am struggling to them to pair onto the system. Alarm engineer charged and advised that they were all set up two weeks ago but not answering his phone now. one unit had a fault on it and noticed the lids were fitted incorrectly and units internals are different although outer cases are all the same..