Everyone, The folks at Sensorcon are willing to pass along a 20% discount to pilots on all of their products.  At checkout use the code below.   http://sensorcon.com/collections/carbon-monoxide-meters Discount code: Aircraft2021 I'm going with the "industrial" and am going to add the Pump kit.  I like the vibrating alarm and the pump kit will help with troubleshooting various applications(home, aviation, boating, etc.) In my opinion, every A&P should have one in the tool