Our low-voltage soldering iron works with any 10W or larger 12-volt Cir-Kit Concepts� transformer or a 12-volt car battery. For added flexibility it may also be connected to track power anywhere on the layout. Heats to solder melting temperature in 3 to 4 minutes. Safest soldering iron yet. Use with CK1033-1 solder or any 60/40 rosin core solder.