These heavy wall flasks with tabulation are blown in special molds in shapes designed to give maximum mechanical strength. For convenience, the flasks are graduated to show approximate capacity. The neck finish affords an excellent fit for rubber stoppers. Tubulation OD on flasks up to 1000 mL is 10 mm. Tubulation OD for 2000-mL and 4000-mL flasks is 12.5 mm.