[Fluorescence]

These are the type I use:

https://www.amazon.co.uk/Zuimei-Reusable-Waterproof-Lightwei...

They fold flat and wouldn't cause much bother in a pocket but I personally don't like anything at all in my pockets. I keep them in my satchel and they are unnoticeable in one of those flat pouch sections that are pretty useless for anything even as slim as a wallet or phone.

They won't last forever but good for a few years so far. They have survived when I have stocked up on canned goods.