The BTYQ-X-4 CO2 is a portable, sampling-type single-gas detector for carbon dioxide (CO2). Its integrated pump draws in gas samples, while the backlit LCD continuously displays the CO2 concentration. Visual, audible and vibration alarms alert users when an alarm threshold is reached.

An infrared sensor provides a measuring range of 0–5% Vol. The rechargeable lithium-ion battery supports up to 10 hours of continuous operation, with a charging time of 3–4 hours. The detector has IP54 protection and is supplied with a sampling tube, calibration/test cap and carrying case.