A fluid delivery device 1000 comprises a piston assembly 1100, a translatable pivot guide system 1200, and a pneumatic aspirator 1300; the piston assembly 1100 functionally acting as the fluid handler, admitting and ejecting fluid from an inlet 1133 to an outlet 1135; the translatable pivot guide system 1200 is a user controllable system adapted to cooperate with the piston assembly 1100 for allowing a user to selectively set the volume of fluid ejected by the piston assembly 1100; and the pneumatic aspirator 1300 is a pressure control system, adapted to cooperate with the piston assembly 1100 and the translatable pivot guide system 1200, for regulating pressure within the piston assembly 1100, effective to allow the piston assembly 1100 to eject fluid during dispensing and to admit fluid during reset; wherein two or more instances of the present invention fluid delivery device 1000 are used together to effect metered fluid mixing applications.