If you ever have to cut things to a certain contour—say to go around some plumbing, or to match some piece of trim—this profile gauge uses lockable plastic teeth to “remember” the shape of any object up to 10" long, making it easy to trace and cut without racking your brain to remember all the geometry you learned in high school.
Even if you can’t think of a specific task you need it for, it’s only $13 right now with promo code 35ZJGYA7, and I promise you’ll be really glad that you bought it at some point, eventually.