Any recs on a BIFL key chain? Those rings always get bent over time, looking for something sturdy. Might just be a flaw in the design because if you can bend it enough to get a key on, you can probably bend it out of shape over time.
I use those and they have lasted me 5 years without issues, you just have to bend them to the side instead of out/in.
If you want anything more durable it would have to be nitinol for the superelasticity and memory effect, but as far as I know you would need to buy some thick nitinol wire and program the shape yourself, and that requires some specialised equipment