All our murrine are made of Murano glass (coefficient 104) and can be used with glass sheet, rods and grits of the same coefficient. Please note: The dimensions are variable. Sopra description you will find the minimum and maximum diameter that you will find Sopra the package. Sopra the site https://zafferano93714.bloggactif.com/27224746/dice-buzz-su-vetro-colorato