Click on photos to enlarge them.The Campagnolo "Peanut Butter Wrench" was originally intended as a 15 millimeter wrench to be used to loosen and tighten crank bolts. In the 1970s it became known as the "Peanut Butter Wrench" when touring cyclists and cyclists on a tight budget used the handle to spread peanut butter. Today it's most popular use is on the the axle bolts of fixed gear and track bikes as in the photo below. It also works on the axle bolts of BMX bicycles as shown in the bottom photo. The old world craftsmanship of this made in Italy tool shines through as soon as this wrench is picked up.