A fan is used for several purposes in your gray room, but primarily to control the indoor climate in your gray room or your large tent. If you grow plants indoors it is almost a must to use a fan with an associated carbon filter to eliminate any odors that may arise. Another advantage of using a fan is that it is easier to regulate the temperature of your room, we sell special fans that automatically turn up the power when your gray room reaches a certain temperature, to bring it down, which is very convenient . An important advantage of using a fan is that it replaces the air in your growing room so that your plants always have fresh air, which is essential for optimal growth of your plants. Are you unsure which fan you need in your setup? Feel free to contact us and we will be happy to answer your questions. If you are looking for a specific fan that you cannot find here, we will be happy to make it your home.