Offered is for one, 2 in 1 Super Smoke Alarm. Great for travel as it is very portable. It may help give you peace of mind in an unfamiliar setting. It requires one 9 volt battery( not included). Works as a smoke alarm and as a door or window alarm with the spring loaded sensor cord. These are new old stock, still brand new in the unopened package. View the photos as part of the description and ask questions as needed. I have dozens of these so I will consider offers on multiple units. Thanks for viewing!