... 1500mm,1800mm,2100mm,2400mm hot air curtains 1,Centrifugal type,Natural wind and PTC heating wind dual ... power off to protect the PTC elements. 4, Fan made in high quality ABS with toughness intensified. ... from aluminium , is corrosion resistance,of high efficiency, low noise, overload protection, and long life-span. 6, , ... Air speed is with High,Mid, Low three switch of speeds, you can choose right ...