An embedding tool is used to heat the wax foundation onto the wired frame. This product is a 12 volt embedder with 4 prongs and requires a car battery to work. As a result, the wire on the frame becomes hot and the wax melts onto the wire. The 4 prongs do not get hot, but the 2 outer prongs must touch the wire in order to embed the frame. This is because it creates a short circuit in the frame wire, making it hot and melting the wax.