... )Material:galvanized steel or aluminum2)Circular(Patent) style air diffuser size:250mm/400mm (Neck diameter/face diameter) ... 200mm/250mm150mm/190mm3)Surface coating: Outdoor polyester powder coating 4)Style: circular(Patent), square, rectangle or special order ... )Supermarket, marketplace2)Service station, toll station3)Underground, air port, bus station 4)School, office, meeting room5)Hall, corridor and ...