TPU Case for Yubikey

My son asked me a few months ago to make him a case for the Yubikey he uses for work. Teraflop's design was among the several I'd downloaded from Printables and printed for him. My son didn't like any of the designs I'd downloaded and printed for him. I asked him to, describe what he wanted, and he said he wanted a rubber cover that protects the whole key without being too difficult to put on his keyring, and wanted the key to function without removing it from the case.

Rather than reinventing the wheel, I used Teraflop's design as the base for this remix. Obviously, this cover MUST be printed in a flexible material in order to function. I printed his cover in TPU, but flexible PLA should do the same job and could possibly be easier to print. I print this as oriented in the STL with 95A TPU. I should have dried my filament first, but I've printed him so many covers he's not been happy with, I had to leave him with something to complain about…