14/20 is one of the smaller taper/ground joint sizes in lab glassware. It has a 14mm tube diameter with a 20mm long ground taper on all the joints. The diameter at the small end of the taper is 12.5mm. The ground glass zone of the tapering joint is 20mm. The top of the taper is 14.5mm. All 14/20 labware is made of borosilicate glass.
