This is a huge apartment, made for having a great time in Budapest. And yes that is a infra sauna, that you can use free of charge during your stay. It is in the dead center of BP. The place is well designed and suitable for 8 person. I am a proud member of the airbnb community so I know what travellers need during their visits and this apartment is the best pick, if you are discovering the city wiht a group! Hope to host you soon!