ASCO™ Numatics Series Mark 8 Directional Control Valves. The Numatics Series Mark 8 is a line of pneumatic directional control valves designed for repeatable and reliable use in harsh or challenging environments. The valve´s modular design permits easy installation and configuration. Its unit-to-base electrical plug permits instant valve replacement without disconnecting piping or wiring. With industry-leading cycle life, Mark 8 Series valves are ideal for high cycle-rate machine applications.