The controller consists of a bulb which is squeezed before operation, combined with thumb lever controls to both aspirate and dispense the solution conveniently and with speed. For additional accuracy, a central button ejects any remaining drops left in the pipette. The inside of the pipette controller is protected from contamination with any of the pipetted liquids by means of a replaceable 3-μm hydrophobic filter. The pipette controller is available in five distinct and striking colors, allowing pipettes to be easily differentiated at a glance.