Each of these "Survival Bracelets" has 15 to 20 feet of 550-pound test paracord inside. If you ever need to use the cord for something, just unravel the binding. When you're done, you can send it back to manufacturer Survival Straps and they'll rewind it for you free of charge.
Most people probably wouldn't ever end up using it, but I think they're pretty attractive in a ultra masculine way. They're available in a variety of colors with either steel or plastic clasps for around $20-$25.
Survival Bracelets product page [SurvivalStraps.com]