Supply the tubes from 6mm to 315mm, and rods from 2.5mm to 40mm O.D 6mm-315mm borosilicate glass tube and O.D 4mm-30mm for borosilicate glass rod: with 3.3 lineary expansion, good waterproof and acid-resistant ,for industrial, chemical, handcrafts&gifts purpose Triangle rod borosilicate glass 3.3