Designed for use in ducting and fume hood applications to ensure adequate face velocity. This device activates both an audible and visible warning when air flow falls below the OSHA standard of 100 fpm - indicating an inoperative blower, blocked filters or improper balancing. The device runs continuously from AC supply using a wall mounted transformer. A velcro backing and mating self adhesive pad allow the unit to be mounted either on the wall or base of the hood. An L.E.D. indicator lamp indicates presence of power to the unit. A test button is provided to confirm both audible and visual alarm operation and a switch allows the alarm to be enabled or disabled. Mini hoods or custom built enclosures. Variety of different face velocities are available.