They seem to be similar to Tubolito and Pirelli tube. I have tried Tubolito and I cannot say I like them.
The tubes are super light and reduce rolling resistance, with Kojak or even a "fast rolling" XC tyre, they feel faster and smoother which is good BUT, the material used to make them is not easy to fix in the event of a puncture; you need special patches and glue and you have wait ~30 minutes to get it to cure.
I rode with some until 3 weeks ago and after 3 punctures within 30miles, I had enough and when tubeless. I fixed them and I have them in case the tubeless sealant fails.
So unless you race and cannot use tubeless setup, I would not bother with these... That's said I will order a set of tubolito in 20" to use in hill climb races only (clean course that last a few miles only).