Large force, wind pressure resistance：Ventilating Cover Hood Strong enough to withstand 200 km/h wind speed, 100KG load pressure, no deformation, no damage，Roof Vents High speed operation, quiet and silent, can withstand wind speeds of 200 km/h Multi-Functional Chimney Cowl Cap: Rotating hood for ventilation pipes, chimneys and air extraction, no noise, no need to consume energy, rainproof, prevent from entering, beautify the exterior wall, roof Principle：Exhaust Covers Utilizes natural wind and natural air convection caused by indoor and outdoor temperature differences to push the turbine to rotate, thereby using centrifugal force and negative pressure effects to discharge stale indoor air. Easy to install: the chimney cap is very light, fast, and can be installed by one person, and can be ly operated on a relatively gentle slope to further expand the installation range. Stainless steel material is very strong and resistant to rust., Manufacturer: KNBHGUJMD