"This Pipette pump is for sucking solution, by using one hand and the fingers to estimate the amount that is sucked into the pipette. The knob can be rotated to suck in the solution and there is a button below to press for releasing the solution. There is a rubber inside that can be attached to different sizes of pipettes 6-105. It is acidic/basic resistant and the parts can be disassembled for the convenience of cleaning. Material used: Acrylonitrile Vutadiene Styrene"