The APC ERGO TOUCH is the smallest and lightest handheld airborne particle counter at just 580 grams, featuring an intuitive keypad menu and monochrome display to show particle counts over three user-selectable channels ranging from 0.3 to 10 micrometers. It has high counting efficiency from 50% at 0.3 micrometers to 100% above 0.45 micrometers, can measure concentrations up to 2 million particles per cubic foot before reaching 5% coincidence loss, and maintains NIST-traceable calibration with a flow rate of 0.1 cubic feet per minute.