Since I have bought a couple of Shimano cranks, I have the wrenches that came with the crank. I would imagine that's were the bike shop guys get their supply. I also had a couple of riding buddies who would 'only let me' work on their bikes. I would keep the wrench that came with their cranks. They didn't know what to do with it anyway ;-) That plus a six pack was my payment to build their bikes. When ever they needed something done that I didn't have the tool for, the price went up to include them bring me the tool.