OPU-2 A is a robust, surface-mounted enclosure, made of white ABS plastic. Owing to its aesthetic appearance, the enclosure can be installed in conspicuous locations in usable space interiors. Its neutral design and compact size make it possible to install the SATEL GSM and GPRS modules inside the enclosure. OPU-2 A is provided with a tamper switch and can accommodate an antenna, e.g. ANT-OBU-Q or ANT-868.