We make and export hard glass shells, exhaust tube, flare tubing used for street lamps, sodium lamp, mercury light. ItemSpec(mm)WT*L ... (mm) NW GW Flare TubeΦ13.5+/-0.31.2 ... +/-0.075*(1175) Usage: Used for high pressure mercury lamp tube, halogen light tube, high pressure sodium lamp tube.Material: high borosilicate glass, hard glass