A pump having a vessel with a hollow interior. An adaptor may be associated with the vessel and include an opening that facilitates selective flow of fluid relative to the interior. A piston may be slidably mounted within the vessel's interior and movable relative to the adaptor. The pump may also include a piston actuator having a first actuator end and a second actuator end in which the first actuator end is operably associated with the piston. The second actuator end may extend outside the interior such that the piston actuator is configured for facilitating selectable movement of the piston within the vessel. A valve assembly selectively attachable to the adaptor to facilitate selective flow of fluid relative to the adaptor.