Natural Rubber Bulb allows safe manual control of filling and discharging toxic liquids through pipette by finger pressure, thus avoiding mouth contact. To expel air from bulb press valve (A) while squeezing bulb. Release valve A. Draw liquid into bulb by depressing valve (S). To expel liquid depress valve (E). (Valves are stainless steel.) Autoclavable to 250 degrees Fahrenheit.