Sigh I hate that crap. I sold probably about 8 of those Mini-Ductors. Not a lot, but at almost $500 a pop, I get it.
I wish I still had one of those MIni-Ductors in stock, I'd make a video displaying it as I do for my customers. My demo was, I took a pair of vice grips and a main bolt from a small block chevy. I walked into each shop, plugged it in, and turned the bolt bright red in front of guys within 30 seconds to a minute. Most guys had seen them before, but had no idea how they worked. It doesn't transfer heat by touching, I liken it to a hot dog in a microwave(though it isn't microwaves). It excites the molecules in the metal, and heats it up from the inside out. All with no flame, and only a bit of radiated heat. The promo material shows they using it to heat up fuel lines to get the connections loose. And gas tank strap bolts. Stuff you'd never(SHOULDN'T) use a torch on.
And the VideoStik is a very nice product. It works awesome and I agree, 90% of its use isn't in a cylinder. People think of it as a "video borescope", I just say it is great for whatever. I can't count the number of times I've used it and shown the backside of a cylinder head. Those times where you go, "it feels like there is one more bolt, but I can't find it". Or "Where is that coolant coming from?" Just LOOK! However I like some of the Snap-On options better for adjustability and a few other factors. Though they cost wayyyy more. The VideoStik is a wonderful option at its price point, that Snap-On can't come close to, unless they sell IT, ha.