This LabGenius Pipette Controller limits over-aspiration! You only need one larger volume pipette controller for the entire range of bulb and graduated pipettes from 0.1 to 100mL. It will accept either glass or plastic pipettes. Simply squeeze the suction to aspirate up to 50 mL of liquid in one compression. To discharge the liquid, simply press down the lever. The valve system is designed so that flow rate does not affect accuracy. The hydrophobic membrane filter cuts down contamination by liquids. A replacement filter is provided. Unit is autoclavable.