The loop valve is the ultimate tool for precision.  It uses a loop valve module and external pump in place of the valves assembly and peristaltic pump that are on the system.  It only dispenses three reagents and has no fill to function, due to loop valves using known volumes for the loop.  It is designed for the laboratory needing to dispense two reagents and DI water or three reagents.  It requires customer supplied compressed air to operate.