I’ve become a big fan of the Nike+ GPS app for tracking my runs, but I’d hate to have a sweaty iPhone slip through my fingers and strike a limestone rock or cement, so a simple wrist strap seemed like a good idea.
Some iPhone wrist straps work by replacing one of the screws in the bottom of the iPhone with a keyring attachment, which results in an extra piece of metal jutting out the bottom of the phone. The ideal solution seemed to be using a locking Apple connector like the one pictured, but those wrist straps cost $7 or more. You can make a very secure and strong strap using any common iPhone cable that has the metal locking connector with button-press release. These currently go for $3.59 shipped on eBay, but I happened to have one lying around. It works perfectly.