Yeah, that's the heat sink. So as to avoid the thermal expansion will be the top of the silicone cover loose, hot water flow out of the burned users.

Xin Xiang Ceramic Mug Manufacturers Co., Ltd located in Shandong province China, which is one of the most famous ceramic producing Area. After experienced 20 years of ceramic business and development, we become a professional and reliable ceramic mugs supplier. Our annual turn-over more than RMB300millons .Our factory have SEDEX audit, NBCU audit, Disney audit, Wal-mart audit ect......

Xinxiang company business include ceramic mugs, ceramic coffee cups,sublimation mugs, tea cups and saucers, fine bone china mugs, promotional mugs, eco cups, musical/melody mugs, color changing mug/magic cups, solid color mugs ,coated mug, dinnerware sets, tableware, couple mugs, plates, bowls ect, Materials: porcelain, stoneware, magnesia strengthen porcelain, fine bone china . There are variety designs and shapes for your selection, customers' own designs are welcomed.