The Helios Fans WDS 250 and WDS 315 are mounting bases specifically designed for installing roof fans and ventilation hoods on corrugated roofs, compatible with RD roof fans inclined up to 25°. Built from glass fiber reinforced polyester, these bases offer a weather-resistant, corrosion-free, and lightweight structure that is also highly durable and unbreakable. They feature low thermal transmittance and a shaft spacing of 177 mm (profile 5). Each unit comes complete with fastening screws, profile rubbers, and a sealing layer between the base and the base plate for a secure and tight installation.