Only rich people will have it.

. . for traditional woks or kadhais. Flat bottom woks are available and may work OK, but not kadhais. The Indian kadhai has the very best geometry for deep frying of any device in the world - way less splattering all over the stove. I use mine a lot.

Of course you can probably use a sheet of steel below traditional clay bean pots, Corning ware, ceramics, borosilicate glass stovetop pots, coffee carafes, etc. probably with seriously reduced efficiency.

Tri-ply pots and pans will work because they have corrosion resistant 300 series stainless on the inside, and less corrosion resistant but magnetic stainless (like 400 series) on the outside, but anything all 300 series won't work. Nor will aluminum.

First of all, they're all 10 inches or smaller, useless for any but apartment / condo dwellers who don't do serious cooking.

Second, some are non-stick. No sane person does deep fry in a non-stick pan.

Third, some are pretty stainless steel. Deep fry in one of those and you'll have to scrub it inside and out with oven cleaner - it'll look terrible. Iron and steel are supposed to develop a black varnish "seasoning", stainless is not.

My kadhai is a mere 14 inches, about the smallest size for general use. India Sweets and Spices down in Glendale sells them them up to about 36 inches. Mine is stamped out of a heavy sheet of steel, and I do mean heavy, it weighs 9 pounds.

A kadhai looks kind of like a wok, but is not at all the same. The radius is different and the sides are higher and more vertical. It is far better than a wok for deep fry, very much done in India, and for which I use it fairly often.

On the other hand, a kadhai is not so good for East / Southeast Asian stir-fry. Recipes from that region often ask to push ingredients up the sides while adding others in the middle. The sides of a kadhai are too steep for that.

Now I do use (but never for deep fry) a 13 inch tri-ply stainless wok, which would absolutely horrify any aficionado of Cantonese stir-fry - it's way to slow to respond to changes in temperature. That's OK, you can't really do Cantonese on a home stove anyway - though J Kenji Lopez-Alt has developed a way to fake it using a map-gas blow torch.

13 inches is a little cramped, but suits me most of the time, as I'm usually doing stir-fry for three or fewer people.

For more demanding work I have a 14 inch carbon steel wok by Atlas Metal Spinning of San Francisco - the best ever made. Unfortunately they no longer make them.

At the same time I bought that wok, 55 years ago, I bought the best Chinese cleaver knife ever made, by Dexter Russel of Massachusetts. I've used it often since then. It is still made, and a recent book by a top expert in Chinese cooking says that just about every skilled Chinese chef in the US uses that knife. They now also make a stainless steel version (at a lower price), but that's strictly for amateurs.

I seldom use this knife for Chinese recipes, but consider it, and a soft faced mallet, to be one of my kitchen essentials - see Chinese Cleaver Knife & Mallet.

And speaking of stuff in production for an unusual time, in the late sixties I purchased a Fluke 73 multimeter. It was just replaced by a new model about 2 years ago. That has to be some sort of record for electronic equipment. A support person once asked me on the phone if my multimeter was sensitive enough for what he wanted me to do. I said, "I don't know, it's a Fluke". His response was "Bastard!" - he apparently knew what a Fluke multimeter cost.

But for something really long lasting - I think it was in the Balkans, many years ago the grave of a lady from Paleolithic hunter-gatherer times, thought to have been a shaman, was partially excavated. It was found to have an amazing amount of grave goods, from an era when grave goods were rare. Recently, excavation was completed - and they found there was a second layer of offerings made at her grave site, 700 YEARS after her death. Now that is fame.