I am not much into jewellery, but I might make an exception for this piece: this one contains a saw and handcuff shim pick combination tool which is completely hidden from view when worn. http://www.uniquetitanium.com/Titanium-Escape-Ring_p_493.html
The Ultralight Hiker
Ultralight hiking, backpacking, bushwalking, deer hunting, canoeing, pack rafting, tips, trails, adventures, gear, reviews...Over 1600 posts & 70 years' experience.