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.

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.
It creates a short circuit in the frame wire, making it hot and melting the wax.