Our safety pipette filler is made of 100% natural rubber for best chemical resistance. Air flow is controlled with polished glass ball valves that will not corrode or freeze up. Pipette fillers are easy to clean when necessary by repeated flushing. Colors are permanently molded into the rubber and will not fade or leach. Pipette fillers are easy to use. First expel air by squeezing valve A on the top of the bulb. Fill pipette by squeezing valve S on stem. To dispense from the pipette squeeze valve E on the side of the stem. Made from all natural rubber Eliminates the need for dangerous mouth pipetting