O.B.D is a special design for regulating the volume of air flow, it is functional but also user friendly. Users are able to adjust all movable blades into any angle in just one turn by using screw driver. This high efficiency was caused by a movable slide bulit and connected to each blade. Due to O.B.D are designed to used on the back of air diffuser, so the size of O.B.D have to be a little bigger than the actual neck size of diffuser.

Round O.B.D has the same function as the square O.B.D. It’s mainly used for Round Ceiling Diffuser. Users are able to adjust the movable blade into any angle manually, to achieve the purpose of regulating air flow.

Bufferfly O.B.D is a new design for Round Ceiling Diffuser used. A new component - Gear wheel, has been added, in order to operate and control easily by using screw driver.