In capsule hotels, each guest stays in a small sleeping space called "capsule". In a capsule, there are a TV, an alarm clock, a light, and so on. The open side of a capsule is shut by a curtain or a screen, and it is unlocked. To sleep well in capsule hotels, earplugs might be helpful.
A locker key is usually provided to each guest to keep baggage in a locker outside the capsules. There are shared shower/bathrooms and restrooms, and many capsule hotels offer a large public bath or a sauna.
Women aren't often allowed in capsule hotels due to security reasons. Please contact hotels in advance. There are capsule hotels offer seperate floors or areas for men and women. Some capsule hotels in Tokyo are listed here.