The Gravitron creates big, efficient hits through gravity and pressure. Start by filling the base halfway with water. Then pack the bowl with dry herb and insert it into the joint at the neck of the bottle. Light the bowl and lift the bottle at the same time. Once the bottle is full of smoke, remove the bowl and place your mouth over the neck, inhaling as you lower the bottle. The Gravitron will give you a dense, pressurized hit with no loss of smoke in the process.
Medium: 9" tall
Large: 11" tall