Glossary
HMD
A metal cap that sits on the bowl instead of foil and holds the coals.
Also known as: heat management device
HMD stands for heat management device. It is a metal cap that goes on top of the bowl, and the coals sit on it or inside it.
The big win is easy heat control: open or close the vents, or move the coals around. No poking holes in foil, and less ash lands on the tobacco.