hunterashmore

Pebble was my watch for years until Garmin released the vivoactive HR. While Garmin loses style points compared to Pebble, it has much better features and durability.

The first weekend I had it, I tested it by wearing it on a Tough Mudder...it survived without a scratch. 2 years later and the Garmin battery life is still over a week. If you miss Pebble and want something still being updated, look at the Garmin watches (but I wouldn't go any lower than the current vivoactive3 line)

Depends on the type of unit you had. A "sensor" certainly should have picked up lower levels, but most "alarms" don't go off unless harmful limits are hit - often calibrated at or above 100ppm, depending on the unit specs.

an addition here - there are two classifications of CO poisoning: acute and chronic. Acute is deadly in anywhere between minutes and hours. Chronic ranges from not deadly to lethal and can be after hours, days, or months of exposure.

Why are we talking about the air filter? a) whether it was a glowforge system is still speculation b) air filters do not have anything to do with CO, only particulate.