4" Inch, 6" Inch, 8" Inch, 12 Inch, 18 Inch, and 24 Inch Borosilicate Pyrex Glass Blowing Tube.
Clear Tubes. 
Outer Diameter: approx.12mm
Inner Diameter: approx. 8mm ID
Thick wall of approx. 2mm.
Smooth Fire Polished End.