construction. The driving cone has 3 slots of 6", 9", and 12â diameter and is accurately balanced. A 0.25 HP motor workable on 220VAC 50Hz single phase operates with the pump. The stroke is adjustable and is graduated up to 250 cc. Motor coupled on adjustable castor wheeled base. Respiration Pump : Single cylinder pump with mechanically operated value. All metal Ideal Respiration Pump (V.R.V.S.): Capacity up to 500 CC.