Come and see our amazing products. 5oz two-layer glass cup is made of high borosilicate heat-resistant glass, which is artificially blown. The product is bright and transparent, safe and lead-free, resistant to extreme cold and heat, and has no fear of instantaneous temperature differences between minus 20 degrees and high temperatures of 130 degrees. The quality has passed US FDA, EU LFGB and other certifications. It is used for drinking milk, coffee, beer, flower tea, green tea, black tea, juice, beverages, etc. It is recommended for home, office, hotel, coffee house, bar or club. Because the cup is mannually blown,air ventreserved during manufacturing.It is not defective,please feel free to use it. Pls confirm further with us if any query about packing info, inventory status and time schedule.