The basic action of turning a nut onto a threaded bolt is something we use every day, and this simple but effective set is the perfect way to teach your child this skill. It consists of a solid beechwood block with three different-sized nuts that screw onto matching bolts. The nuts and bolts are  both made of high-quality stainless steel to resist rust and corrosion. The block measures 20 cm (about 8") long.