... 3.355mm -1600mm specification 4. Bothway fan Jet Flow Ventilation Fan for tunnel , subway Introduction:SDS jet flow fans is specially ... pressure 380V, frequency level F grade, protective level IP54 4. K style fans inverted pressure air is 0.72- ... is same whatever inverted pressure and positive pressure. 5. SDS fans can work at -25°C to +50°C, ... Parameters: Tunnel Subway special fans Jet flow fan(SDS)