The Alnor Airgard lab hood monitor model 405-D indicates safe levels of air flow in laboratory fume hoods. It is used to measure and report on exhaust flow in many critical or controlled indoor environments, including pharmaceutical and university laboratories. The Airgard 405 monitors is a simple, low-cost option for your monitoring requirements. It features an audible and visual alarm with relay output in an easy-to-calibrate unit . This surface-mounted model is designed for easy retrofit to existing hoods.