I don't think I've ever cut a piece of drywall in my life, but if I ever do, I will surely want this amazing tool. The Drywall Axe is a combination of a retractable blade along with a measuring tape, so that you can measure the length of the piece you need to cut ahead of time, lock the tape measure in place, and then precisely cut the length of the drywall while keeping the exact measurement at all times.
Simply pull out the tape measure from the body of the device with the blade on the end of where you need to measure from, lock the tape measure in place using the tab by your thumb, and physically move your locked-in measurement to your piece of drywall. You can then just drag the blade and the edge of the tape measure simultaneously for a perfect cut every time.
Not only great for drywall, the Drywall Axe also works great with a variety of other building materials. A nail hole near the end of the tape measure helps you hold it in place, and a built-in slot for a carpenter's pencil in the body of the blade is also great for added versatility, repetitive tasks, or measuring a full length rip cut.