You’ll need a flush installation box to install the 2N IP One intercom. This accessory is necessary for you to mount it on variety of surfaces.
2N 91378803 intercom system accessory Surface mount box
2N 9155048 intercom system accessory
2N 9155101 intercom system accessory
2N 9151918 intercom system accessory
2N 9155050 intercom system accessory