The VICKEY3 Multi-Tool Drum Key comes with a number of tools to handle any kind of emergency or adjustment you might need to make at a gig. It includes a 4mm hex wrench, a 3mm hex wrench, a Philips head screw driver, and a snap-on drum key bit that can attach to the 4mm hex.
This tool is constructed from steel, meaning it will survive any beating on the road. It will be the only one of these you need to get. The carabiner attachment makes it easy to clip this to a stick bag or backpack.