It's in the form of a tiny PCB that attaches to a DC jack and auto-disconnects when too much voltage is connected, or the wrong polarity.
Instantly with no heat, unlike a polyfuse.
Also with around 0.1 Ohms series resistance. The lowest I could get a PTC was 5ohms - interesting fact.. some datasheets state lower, but this is if the PTC is socketed. The reflow process causes an irreversible change..
Going to send the first ones out with a minimum quantity of 40pcs in a V-cut PCB panel @ 59usd shipped anywhere - more for tracking..
You can find a video and pictures of it here https://www.instagram.com/p/BoGaK7nlrA8/
