It is a double stage pump to create vacuum through a diaphragm, where continues operations are required without the fear of sample contaminations through oil vapours where even a slightest environment contamination through oil must is forbidden. To work on 220/230 volts A.C.(a) Capacity 25 ltrs./min. Air displacement (DOUBLE HEAD)(b) Capacity 45 ltrs./min. Air displacement (DOUBLE HEAD)