Precision ground glass stirring shafts, 19mm OD, hollow, heavy duty. Knob type shafts accept 8091,8092,8093,8100 agitators and can be used in all 19mm ID Trubore 8059, 8060, 8061 and 8065 bearings. Compatible with our 8050 mechanical seal and 13445 PTFE Debris-free bearings. Join to stirrer motor using 8124 series chucks. Heavy duty design intended for use with large flasks up to 72 liters.