Abstract: A dispense head assembly comprise a housing, and a body having a fluid inlet and outlet attached to the housing. A piston is disposed within the body and housing and is attached at one end to an actuating handle. A poppet/diaphragm is attached to the opposite piston end and includes an imperforate head, a thin-walled sleeve that extends axially away from the head, and a tongue that defines a terminal edge of the sleeve and that forms a leak-tight interference seal with the body. The poppet/diaphragm sleeve is rolled between opposite piston and assembly wall surfaces to provide open- and closed-flow poppet/diaphragm movement. A dip tube adapter is releasibly attached to the housing and body. A tongue and groove seal arrangement is used to form a leak-tight interference seal therebetween. A dip tube is attached to the second adapter body end to provide fluid pick-up from a fluid container to the dispense head assembly.