Nonselected port(s) vent to the atmosphere. The valve has detents for manual operation with a knob or can be configured without detents for automatic operation with servo or stepper motors. An optional configuration (with built-in check valves) switches input ports (two through six) to a single output port for sampling pressure readings at multiple locations. Readings can be fed to a common pressure gauge. The valve head outside diameter is just over 1 in. and its length depends on the choice of tube fittings. But typical length is about 1.6 in. Beswick Engineering Co. Inc., 284 Ocean Rd., Greenland, NH 03840, (603) 433-1188, beswick.com