The ASA Carbon Monoxide Detector has been redesigned to meet National Transportation Safety Board (NTSB) recommendations.
Company officials report that the detector features a spot sensor on the front that darkens when harmful levels of carbon monoxide are detected, and then returns to its original color when the air freshens.
A “date opened” feature allows for recording the date the package is opened and serves as a reminder to discard and replace the detector when it expires.
An adhesive strip on the back attaches to an aircraft instrument panel for a semi-permanent installation.
Unopened CO detectors have a shelf life of three years. Once removed from the packaging, the detector will last for 12 months, according to company officials.
Price: $4.95.

If what you are protecting is worth more than $5, don’t go this route.
Get a BW Gas Alert Clip or equivalent & leave in cockpit.
This is news? I just buy them and use them.