Barbara,
I have used one of the Petite Press irons. They have a pretty weak handle that prevents using much pressure to seal the seam, and they are low wattage, if I recall it is a 40 watt iron. It’s owner found it very slow to bring a seam up to temperature and seal. He gave up and got a model aircraft iron.
As others have noted, the 165 watt model aircraft irons have been in very short supply. Perhaps R/C enthusiasts are all building drones, and no one heat seals light fabric onto model aircraft?? Who knows. At this instant, RC Planet has the Hangar 9 for $19.99. The Hangar 9 irons I have did not require internal adjustment of the thermocouple. They just need to have the sides ground to a nice 1 cm flat usable surface, and I like to grind a clipped nose I can tip upside down and get into folded or overlapping seams. Grinder, file, and/or sandpaper is all you need. I really like the amount of heat, and the ability to flip it from side to side and have a fresh hot surface. Use your infrared digital thermometer to make sure it stays between 205 and 225 degrees.
I agree with Matt that the Ali express adjustable, 150 watt, leather irons are the best and most available. The hard part is finding the key search words. I googled “Ali express leather iron” a couple minutes ago and was given several choices, including one for under $10 with free shipping. They are normally $21 to 35. I bought simple white plastic plug adapters. Matt opens them up and simply rewires them to a 120 plug, I’ll do the same – one of these days. I then paint the sides with High Temperature Flat Black Stove paint. This allows me to check the temperature with an infrared thermometer. Alas IR thermometers can’t read bright shiny reflective surfaces. I tape the temperature dial to keep it from getting bumped. And I recheck the iron temp frequently. These can get way to hot! The upturned tip is really nice for tight corners and seams.
Hope this helps.
Bruce