What about the lowly keyring? Every time you want to add or remove a key from a substantial keyring you risk damaging a fingernail and futzing with the split in the ring always seems to take more time than it should.
It looks like the Tang Ring keyring has improved the keyring. One disadvantage of living in Mexico is not being able to get certain things that are available in the US. It’s not a big deal but next time I’m in the US I’ll get some of these to try out.