Scary-sharp cutting tool

I’ve always used a razor knife to cut fiberglass insulation, but I recently found a new tool that works better. A rotary cutter is a tool used by a sewer (rhymes with blower, not bluer) to cut fabric. It has a round, scary-sharp razor blade that rotates as you pull the handle toward you. Be very careful when you use a rotary cutter;  it slices through stuff so effortlessly that it’d be easy to nip off a fingertip. When I used one recently to help a friend insulate his addition I put a plastic kitchen cutting board on the subfloor and cut the insulation against it, figuring it would make the blade last longer. Although the rotary cutter was designed for fabric, it works great for fiberglass insulation, and I can see it working equally well to cut wallpaper, vinyl flooring, and house wrap.