... ,lowe noisy,CE certificate JCD series high-grade type heavy hammer exhaust fan features.1. Certificate, CE.2. Frame, all the ... .5mm thickness. Galvanizing layer , 160kg/m2.14. Opening system, heavy hammer.15. Rivets, aluminum alloy and stainless steel rivets.16. Cable ... wire.17. Warranty offer, 2 year , the whole machine. swung drop hammer shutter exhaust fan