Familiarity: I've used it once or twice and have initial impressions
and carry this for a spare. Recent trip riding in park city resulted in a tire getting a good sidewall gash that sealant wouldn't take care of. This is replacing the tube I donated to the occasion. Removable core so you can dose with sealant if needed. Its a tube--I use one a couple times a year only to get back to civilization if needed--then its pulled in order to get the wheel back to tubeless.
These tubes are tubes, they do the job just fine. The valve cores are removable and the valves a perfect length. I wish they came in two 27.5 sizes rather than one - a more compact tube spare tube for my 650x47 tires would be nice.
Like most other Mountain Bikers, I ride tubeless tires and only carry a tube in case my tubeless system fails on the trail. I like Continental's tubes for this purpose since they are made to fit wider tires and have a nice long 42mm valve. Some other tubes have a 32mm valve that can be too short for the wider-and-deeper rims that are on a lot of newer bikes.
Great tube to carry on the trail for unexpected flats. I use a voile strap and keep one attached to my bike any time I'm doing a longer ride. They are also quite a bit cheaper than other alternatives and seem to be just as good.
Continental makes great products and this is no exception. These tubes hold up to abuse and are less expensive than many other options that are very similar. If you are looking for an extra tube to carry along on your ride these are a great choice.