Russian company sells Kodak LR-115 Type II, but I'm not sure if they ship internationally, because they don't even have an English version of their site. Anyway, you can use Google.Translate: https://gruppa-rei.ru/page/159
A consumable kit for 300 measurements of radon concentration (using REI-4 diffusion chambers), which includes film, sodium hydroxide and aluminized tape, costs about $1,420 domestically.