I wish I'd seen this a day or two ago.
Anyone have any experience with: https://www.amazon.com/dp/B076S6KBP2?psc=1&ref=ppx_yo2ov_dt_b_product_details
CO Detector So you don't die! Very cool
Beware that some of those cigarette lighter ones are noisy as hell, electrically. My friend brought one along and plugged it into my airplane to show me and after we started up I couldn't figure out why I suddenly had an obnoxious squeal in my intercom. Turned out it was the cigarette lighter device.
I use this device and it works well (alarm is loud, and I have heard it when taxiing with the door open) and the batteries last at least a couple months.