Professional Carbon Monoxide Test Kit & Detector, Detects Invisible & Odorless Gas, Stick On Carbon Monoxide Detector Safe & Easy To Use, More Sensitive Than Electronic Detectors & Provides Accurate & Reliable Results, Replace Sensor Button Every 6 x Months, Un-Opened Sensor Buttons Shelf Life Is 3 Years, Great For Use In Boats, Airplanes, RV"s & Automobiles, EPA Approved Lab Methods, Contains Detector, 2 Reusable Sensor Buttons.