It's also foam. I'm against foam incubators, pretty much because they seem easily broken if knocked off a table, & difficult to clean, & sanitize since it's a porous material.Forced air. This is the same exact model I have, I just bought mine locally instead of from Amazon:
https://www.amazon.com/gp/product/B00TTYLIKY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Forced air is good. I always use forced air, since heat is more evenly distributed. But cold spots still maybe possible depending on incubator size though.