The entire Crystal collection is made of 100% hand-blown, premium Borosilicate glass. These items are of the highest quality, and represent the most vibrant and durable glass products available today. Crystal items can be heated/cooled to personal taste. No matter the size, our Crystal glass plugs are a stunning display of erotic art. This beautiful design is available in 3 different sizes, with 2 color options available per size. The large Crystal premium glass plugs are 4" (100mm) tall.