These heavy wall round-bottom flasks feature standard taper outer joints on the center neck and twenty-degree angled side neck. Flasks with a 29/26 center neck have a groove tooled just below the grind to aid in clamping of the flask. Flasks with 10/30 side necks are for use with CG-3506 thermometers
Additional joint sizes are available by special order. For 2-neck flasks with straight (parallel) necks, see item CG-1518.