The Helios FDS 500÷560÷630 Purlin Box is a robust mounting base with an integrated hinge mechanism, designed for installing RD series roof fans and ventilation hoods on flat roofs. Suitable for horizontal installations with up to 25° inclination, this base is made from corrosion-resistant GRP, offering durable, abrasion-resistant insulation for sound and heat protection. The unit ensures a snow-proof base height and comes complete with fixing screws, profile rubber, and sealing to provide a secure and weather-tight connection between the fan and base plate. Ideal for long-term rooftop applications where ease of access and reliable performance are essential.