Titanium Saw Ring. It's a simple but elegant-looking ring made of titanium. But unlike all other rings, this one contains a saw and handcuff shim pick combination tool which is completely hidden from view when worn.
Coin Cuff Key - "designed for a specialized elite U. unit whose members are at high risk of being taken captive and require improved odds of escape. -- lots of stuff on this site that can be dangerous to keeping criminals in custody.