The MUYA WT8821 Oxygen Monitor is a compact electrochemical-sensor instrument for spot-checking and monitoring oxygen levels from 0 to 25% VOL, with a fast sub-15-second response to changing conditions. It supports MAX/MIN recording, adjustable alarm thresholds, field calibration, and both C/F display, giving safety personnel flexible control over how readings are tracked. Running on standard AAA batteries with auto or manual shut-off, it's built for portable, on-demand oxygen safety checks.