1.good material 2.cheap price We offer borosilicate glass tubes and rods with various colors and size . C.O.E3.3±0.1(10-6k-1)Available colorsClear, Opaque white, opaque black, transparent black, Dark blue ,light blue, amber, yellow, green, pink,Purple, redRegularly stocked tubing size7x1.5mm,8x1.5mm,9x2mm,12x2mm,12x2.2mm,13x1.8mm,16x1.8mm,16 x2.4mm,19 x3mm,50 x5mm,50 x7mm,50 x9mm,60 x5mm,60 x7mm, ...