Metcal dx 250 series digital dispensers metcal dx 250 the metcal dx 250 digital dispenser controller is an economical highly accurate and repeatable micro air dispensing systemthe system includes a digital timer and vacuum control for all types of fluids and operates from a pressure of 0 to 100 psi for general applicationsthe dispenser controller is supplied ready to use with a universal power supply foot switch air hose sample tips syringe barrels and adapter metcal dx 250 digi