Flask features a protective PVC coating for longer product life and safety. Protective coating helps prevent glass from shattering and reduces spills. Autoclavable (121°C) and resistant to thermal shock. For convenience, the flasks are graduated to show approximate capacity. 10mm tubulation OD on sizes up thru 1000mL. 12.5mm tubulation OD on 2L & 4L sizes. The tubulation is not coated to allow easy connection of standard size tubing. PLEASE NOTE: DO NOT PLACE OVER DIRECT HEAT OR FLAME. DO NOT HEAT ABOVE 121°C MOIST HEAT OR 110°C DRY HEAT.