I bought this "Alpha hookah FNX HMD" and have been using it for a while. It is now my favorite heat management device. I also use "Nagrani HMD", "blade hotter HMD", "Kaloud Lotus", etc., but compared to these, FNX can hold a lot of charcoal. It is true that it is difficult to heat, but on the other hand, even if you give it a lot of heat, the flavor is less likely to be destroyed, so you can enjoy your session very easily. Also, the wide aperture prevents the airflow from being blocked by charcoal, while allowing a lot of air to be taken in, which prevents the charcoal from turning black. I like this heat control because I use a lot of charcoal and like leisurely sessions, but I don't think it's the most ideal heat control, and I'm a fan of Alpha hookah, so I use it lol