If you can figure out which symbol it is. (My mom in the US bought a german oven, and each nob is a symbol, which means something fan, line, squigly line...). Once you know it makes sense, and this is a case where the internet helps.

(symbols like:) https://www.ebay.com/itm/173568522355

but in the US convections ovens are not that common.

I had in the 90s the faberware "turbo oven". It was too big for me but it was a convection oven and quite fast. Caterers that did functions at the museum I worked hauled them in to heat food.