Thicker gauge steel tends to make for sturdier design and gives a heaviness on the cocktail shaker. While quite a few Boston shakers are made of tin for more secure shakes, the glass rim on this Kotai shaker is tempered—the rim is heated up and cooled down for durable glass https://ricardomhzsj.bloggerchest.com/37490104/little-known-facts-about-shaker-cabinets