Meet Jamb Tac, available from Painless Performance Products. It features solid brass connectors capable of moving a whopping 60 amps of current that remains very isolated from the metal of the doorjamb. That means you can pass either negative or positive voltage through them. They’re also available in single-, two-, three-, and five-contact versions. The plastic nuts on the back of the Jamb Tac allow adjustment of the brass for different width doorjambs.