Dockable GasBadge Pro uses interchangeable smart sensors to monitor unsafe levels of oxygen or toxic gas. It includes STEL and TWA readings, datalogging of up to 1 yr of survey data, and event-logger that records past 15 alarm events. Housed in rugged enclosure, water-resistant and RF-immune monitor displays gas readings in % by volume or ppm. It alerts user with audible alarm complemented by vibrating and visual alarms when gas concentrations exceed limits.