Carbon Monoxide Detector - Portable Credit Card Size Minimum 18 month sensor life Affords protection at broadest range of temperature and humidity Multi-level Detection - Normal=Yellow, Caution=Green, Danger=Dark Blue Biomimetic Technology - Responds to CO in manner similar to the human body Rapid sensor regeneration Unique Packaging - Customer assembly not required 1-step activation eliminates possible sensor contamination by end-user Sensor is protected against accidental contamination Operation Range - 41-100 degrees Fahrenheit, 25% to 90% relative humidity POTENTIAL USES - Aviation Cockpits, Workplace, ID Badges, etc. PLEASE NOTE THE SHIPPING AND RETURN POLICIES NEAR THE BOTTOM OF OUR HOME PAGE. THANK YOU!