With a penetrating volume of 85 dB (A) and an optical signal in the form of LEDs, the X10-D.2 alerts users to elevated carbon monoxide concentrations. A green light indicates operational readiness, a red light signifies an alarm state, and a yellow light indicates a malfunction. The alarm itself is regulated according to EN 50291:2010 and is tiered based on the concentration of carbon monoxide in the air: Concentration of 50 ppm (0.005%): 60 to 90 minutes until alarm activation; concentration of 100 ppm (0.01%): 10 to 40 minutes until alarm activation; concentration of 300 ppm (0.03%): less than 3 minutes until alarm activation.