I got this cheap flashlight, looks ok, have a "cheap" feeling of it (because of the light weight, but it's actually not a bad thing) and it's waterproof. I tested it in a bottle of water (as you see in the video). There is nothing special function, just an on/off button. The light is not too bright, but it's fine. I think it worth the few bucks I paid for it. I'd say it's ok for a +1 flashlight in an EDC or just having it on a keychain.

I thought it's just a plain blank one, but it's marked "Police 3w".

https://www.youtube.com/watch?v=PoXMQzEMCs4

You can't buy a Big Mac for $3, so good for you.  Nothing 'POLICE' about it, but if it works and works for a while, you're fine.  Use it as a beater, or as a loaner to neighbors that don't give shit back.

Chris