How much is the F10 stroller air and where can I order it? Are they available in the US?
The Gesslein F10 costs about 750 to 1000 EUR (which is around 880 to 1200 USD) as it's a premium, rather high-quality pram. The price actually varies quite a lot depending on how many accessories does the parent need, if he/she prefers a hard-bottom bassinet or one of the two insert carrycots, etc.
Unfortunately, as a German brand, Gesslein is not available in the US, as far as I know. You could look on eBay and similar global platforms but, as they focus in the newer models (like the Gesslein FX4), you probably won't find it shopping to the US.
Some people do travel to get the stroller of their dreams, but I think it might not be worth that much time and money in these covid times... Sorry I was not more of help, but as we're no selling strollers, I can't do more than provide information. Do check fixed-wheel strollers like BOB or Thule to find similar quality and functionality, even if they might be three-wheelers.