Topair’s Polypropylene Ductless Fume Hood – PRO provides a safe work environment for lab staff working with acids and harsh chemicals. The hood includes an advanced VAV (Variable Air Volume) system. The VAV system measures the product’s air velocity using a high quality sensor,and adjusts the air velocity speed to the relevant standard. Maximal energy savings are enabled by flexibly adjusting the fan speed (high/low) as needed. The system features a high safety level,displaying real time air velocity and providing alarms for low velocity levels,thus reducing the fume hood’s noise level.Advanced Operation System 9″ color touch screen Hour counter for filter Filter replacement alarm for HEPA/Carbon filters Sensor for temperature and humidity The products are EN-14175 / CE / ASHRAE 110-1995 certified. Chemical Sensor Alarm Samples the chemical level after filtration,displays PPM results and alerts upon low filtration efficiency Red Light Alarm A red light inside the unit switches on whenever there is any kind of a failure (including chemicals or air velocity failures) while the system light switches off. This enables convenient detection of failures,even by people with hearing issues,and from a distance.