The XL 300 Flex concrete installation housing without transformer is used for installing LEDs, low-voltage halogen, energy-saving lamps, metal halide lamps and compact fluorescent lamps. The luminaire installation housing enables tool-free and absolutely concrete-tight pipe insertion for pipe sizes M20 and M25 using the Primo membrane technology. The installation housings are nailed to the formwork on the construction site. For maximum flexibility, the Primo boxes can be provided with individual installation openings on request, which are simply knocked out on the construction site. The box is closed with a metal plate for increased stability and optimal heat dissipation. In addition, the metal plate offers maximum resistance to impact.