I'm looking for something thin that my dad can put in his wallet. The thing is that I would rather he have something that goes on his key chain rather than an app on his phone. I think he does have bluetooth on his phone but he doesn't know how to use apps. He just started texting a few months ago. So any ideas for something dead simple? I also have to buy him another wallet (ugh) fortunately the wallets I get him are only $20.