Hard to say, but Omega definitely care enough about their brand and reputation to have a good QA system and testing of products in place. Since testing that a CO monitor is working is very hard for a consumer, you rely a lot on trust in the brand.

If you can get a good, trusted brand for home CO monitors, I'd say go for it.

Apparently, Kidde is a trusted brand in fire alarms etc. in the US, so I think this one ($20) is probably equally trustworthy:

https://www.amazon.com/Kidde-Battery-Operated-Carbon-Monoxid...

Anecdotal: I've bought cheap versions of things online enough times that I don't want to do it again (just got home from helping a friend install a battery that didn't even fit properly). I've had a few things melt and a couple explode..

I shudder to think that you would risk your life on a device of questionable quality.

>I shudder to think that you would risk your life on a device of questionable quality. //

The problem is surely knowing whether the expensive equivalent is just the same internals in a different retail pack (with other 'quality' signalling). That's genuinely hard for something that needs a lab to be tested.

A CO "monitor" is permitted to alert at low levels of CO (10-20 ppm). A UL-listed code compliant CO alarm may not. I personally think this is silly.

There are a few companies that sell low level CO monitors for residential use. They're all somewhat pricey.