The Libbey 1639HT Restaurant Basics® Mixing Glass is heat treated by Libbey's signature Duratuff™ process for added strength. Libbey's Duratuff is a special thermal after-process that strengthens the upper portion of the glass, which is the area most vulnerable to breakage, giving the glass a prolonged service life.

Mixing glasses are one of the most common types of glassware because of their versatility, used in bars and dining rooms to serve beer or water, or for use with mixing ingredients for cocktail creations.