Due to its size, a spirit level can get beat up inside of a tool bag. Festool has come up with a nifty way of keeping theirs safe: Their design slides right into the handle of the Systainers that all of their tools come in. The little spring-loaded green blister locks it in place. The bottom of the level is notched so it can ride on a pipe. It's made out of anodized aluminum, and runs $65.