Wheels Manufacturing Hanger Multi-Tool
$36 / wheelsmfg.com
Multi-tools are great on occasions when things rattle loose, but when you mangle your derailleur hanger, you're generally SOL. Unless, that is, you've got this multi-tool in your pack. In addition to sporting allen wrenches, screw drivers and a T25 torx wrench, it also packs a universal emergency derailleur hanger that attaches to any dropout and lets you get back home without turning your bike into a singlespeed.