Worst tubes I've used
I used to think tubes were tubes. How could they mess up such a simple product? Why pay $5-10 for premium ones? Well, apparently, the process of making tubes is a delicate process and hasn't been perfected over the centuries by all. Cutter must've picked up a clueless start-up as a source, that or their rejects are being supplied.
I major design flaw is likely the unthreaded valves that don't screw down to be secure against the rim. 2 out of the 4 tubes developed slits right around the base of the valve, which cannot be patched. You can't even use the valves for ghetto tubeless, for when you get sick of flats with tubes, since they can't be tightened down to seal the valve hole. Also, if you inflate it outside of a tire, you will find some sections bulge out in a shape that looks like an muscular arm with big forearms and massive biceps--if that's any way to judge for poor quality, these would be a showcase winner. I think their best use is to simply act as big rubber bands.
To top it all off, these are more expensive than other generics. Don't waste your money. Try Q-tubes for some quality but inexpensive tubes.