Each Grav Sip series pipe is modeled after a famous drinking vessel. Each glass has been reimagined as a water pipe. This piece is the perfect size and shape to fit hands, cupholders, and coasters, and it packs a lot of water filtration into a small footprint. In addition, the 14mm recessed Dewar-seal joint sits flush with the upper edge of the bubbler, maximizing its internal volume. Try looking at the GRAV Milk Carton bubbler, a fully functional water pipe that should remind you of simpler times in the cafeteria. The open body allows for plenty of diffusions, while the narrow opening at the spout of the carton prevents splashback. This familiar design conceals an effective bubbler. The perc and smoke pathway are built into the mug's handle. Great hand-feel and an ample bubbler chamber combine to make the GRAV Coffee Mug one of the most pleasant smoking experiences in a long time.