19/22 Glassware is a taper ground joint standard used in laboratory glass. The 19/22 glassware is made of borosilcate glass and is manufactured according to ASTM E676. 19/22 has a 19mm diameter and 22mm tapering joint length. The small end of the taper is 16.6mm in diameter and the diameter a the top end of the taper is 18.8mm.