An XT60 smoke stopper that has an interal 2A fuse to protect your electronics from a short that could fry expensive gear.
Plug this in between your battery and your quad to test your build for shorts. Any short higher than 2A will trip the fuse and save your build!
Note: Solid State Smoke Inhibitor/ Lightbulbs / Fuses / Circuit breakers are not a 100% foolproof way of keeping the magic smoke in. It’s always best to use it in conjunction with a multimeter.