The OPU-3 P is a robust surface-mounted enclosure made of white ABS plastic. Due to its aesthetic appearance, the enclosure can be installed in prominent locations within usable indoor spaces. The base of the enclosure can be recessed into the wall, allowing the actual enclosure to take up less space. Its neutral design and generous size enable the installation of various types of SATEL control panels, their expansion modules, communication modules, controllers, and a large number of other devices inside the enclosure. The installation and maintenance of system components are further facilitated by the use of special mounting plates. The OPU-3 P is equipped with double tamper protection against opening the enclosure and tearing it off the wall.

The enclosure provides ample space for the installation of 40-VA or 60-VA power transformers and can also accommodate a 7-Ah or 17-Ah, 12 V backup battery. Since it neither blocks nor weakens the radio signal, wireless devices, including their antennas, can be installed inside the enclosure.