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.