High Resolution Graphical Display Menu-Driven Software Functions Automatic Zeroing and Ranging LED Light Source (Light Chamber) Reference Settings for Multiple Testing Reagents Retains Reference Settings When Powered Off Displays Upstream Ref. / Concentration Setting Stable at Low Concentrations of Aerosol (≥ 10ug/l) Probe Selectable Audible, Visual, Vibrating Alarms Plug and Play Probe – 11 foot length USB Interface. Lightweight Heavy Duty Black Aluminum Case Detachable Shoulder Strap Accepts Worldwide Operating Voltages Storage Area for Probe and Accessories.