1,Type:round 2,Size:80mm--250mm 3,Material:galvanized steel 4,Color:RAL9010.RAL9016 5,suitable for offices, buildings,hotels exhaust air valves are designed for installation on the ceiling or in a wall,- Made of zinc-coated steel,- Painted white (RAL 9010),- Easy air flow adjustment by turning the central part,- The blocking nut makes it possible to adjust a minimum slot,- Special design ensures ...