https://www.amazon.com/Sting-Fixed-Blade-Knife-Sheath/dp/B00180CYFA

the original is better... this one clangs on the ground like a wrench when you drop it because of the one piece forged body, but it's got one of the better sheaths i've seen in any knife, it can literally be worn upside down like a chest rig or garter (for a woman)

oh yeah, lol, https://themartialist.net/a-g-russell-licensed-the-survivalist-sting-dagger/ this is an even better, proper one, and look, dual chest rig!

these knives are maybe one of the best stealth fighting knives i know of... and i believe that anywhere the double edge doesn't make a difference to regulations they are short so they are not prohibited to own (pretty sure portuguese knife law allows them to be this size and double edged)