... Description:1)Material:galvanized steel or aluminum2)Circular(Patent) style air diffuser size:250mm/400mm (Neck diameter/face diameter) ... /250mm150mm/190mm3)Surface coating: Outdoor polyester powder coating 4)Style: circular(Patent), square, rectangle or special order.5) ... :1)Supermarket, marketplace2)Service station, toll station3)Underground, air port, bus station 4)School, office, meeting room5)Hall ...