This 1000mL KONTES® safety-coated filtering flask is manufactured from heavy-walled borosilicate glass to assure the mechanical strength needed for vacuum filtration. It has a No. 8 rubber stopper joint and a No. 2 hose connection. The side arm accepts standard 1/4in (6 mm) inner diameter tubing for connection to vacuum sources. A second flask should be connected between the filtering flask and the vacuum source to prevent accidental entry of the filtrate into the vacuum line or pump. Flask Style: Filtering. Material: Borosilicate Glass. Feature: Safety-Coated. Rubber Stopper Joint: No. 8. Hose Connection: No. 2. Capacity: 1000mL. Note: This flask is regulated as precursor glassware. Everyone in the state of Texas must have a state permit to purchase. Kimble® #: 953760-0000.