The Topeak Hexus II Bike Multitool is a really useful tool to keep in your saddle bag. It's got a whole load of different tools and great for tightening up loose bolts, fix your chain, reassemble your pedals etc. I use it right from the break down and boxing of my bike to the disassembly and reboxing and everything in between. I highly recommend taking one as I have used it on every tour.