Detector is designed to turn dark brown to gray/black when exposed to high levels of carbon monoxide.  Even slight darkening may indicate a dangerous level of carbon monoxide.  When the air freshens, the spot will return to its original color (copper), unless over exposed, and it is ready for use again. Adheres to aircraft instrument panels, boats, RVs and more.  To keep your passengers and yourself safe, add this detector to your pilot supplies.

• Concentration Reaction Time Coloration:
  10-20 ppm 60 minutes Copper (i.e. no change)
• 
  40-50 ppm 15 minutes Slight darkening
• 
  95-105 ppm 5-10 minutes Light to medium copper
• 
  150-160 ppm 8-20 minutes Medium to dark copper with brown specks
• 
  195-215 ppm 4-6 minutes Dark copper to brown with dark specks
• 
  400-500 ppm 2-10 minutes Brown to dark brown with black specks