I just bought one of those for another car. How it works is the white plastic is the insulator. When the green screw is tightened down in makes contact with the top plate allowing the electricity to flow through the connector. When you unscrew it the top plate is now not connected and the green screw is isolated because of the white plastic piece. I had to study it for a minute or two to figure it out.
There are a lot of very cheap knockoff versions of possibly questionable quality. I got one made by GAMMA, a US-based company. It wasn't that much more.
Hi, I’ve seen only one of these before,
friend had issues with it, I didn’t trust that piece of thief UHMW to Isolate power. I scrap what I don’t trust, at all voltage/current levels or not.
I run, simple, positive stop rotary switches. (Similar to Pic.below). Have seen the type your running made by Moroso & a few others, I was also able to study one, the knob to Spline that held it
failed, I machined a couple of flats on the shaft, drilled & Tapped the knob with 10-32 set screws to land on the flats
& charged nothing, he put 10$ in my toolbox. Found they could be bought new for additional costs, afterwards
(Brother in law).
But, like all parts, there’s the good designs, then the “Copycats” that mass produce them with cheap components; turning a higher profit. Proof of long term usage without fail works for îme.
Years of usage of the type below are mandatory in my race class & like the rules, they’ve evolved, too.
They’re now available with a deadman’s switch which deenergize select system based on G Sensors that you locate where you desires, setup with a (+) Terminal & fusible link(s) for your needs. Can handle 300A.
I’d find the Original MFG, only because you don’t end up with a loose connection & set off a light show near your Battery. They’re the ones which went through the N.D.T. & D.Testing & repetitions over time before they became a legitimate product. Just my 2 Cents.
I wish you luck!
-John