Dinglab 500PCS,100mm,Glass Melting Point Capillary Tube,4",ID 0.9-1.1 mm,Both Open Ends Capillary tubes are open on both ends. Approx 500 in tube. Length 100 mm / 4" ID 0.9-1.1 mm Wall Thickness 0.1-0.15mm Borosilicate glass