Der Boiler is a men only gay sauna. It intermediately became so successful that all other Berlin saunas quit. It's a large place, the number of cabins is limited however. On busy times often there is a queue outside to get in.
After entry you get 1 towel for free, extra towels can be rented for a small price. The shower area includes soms hygienic showers for a full cleaning.
For relaxing there is a bar and outside garden in summer.
The main facilities include a pool, a Finnish sauna, a more mild bio sauna for a longer stay. A hot Hamam. The main cruising place is the steam labyrinth.