BioTest Airborne Particle Counter APC 942005. This unit powers on, but it was marked “needs calibration” I can’t get it to read a particle count. When the start button is pressed I can hear it drawing air in, but I do not get a particle count reading. So this is being sold as a “PARTS OR FOR REPAIR UNIT”. This does have minor cosmetic wear.  This comes with the power cord and another filter. You get everything pictured. This comes from a smoke free, pet free home