Proportion-Air”s QB3 electronic pressure regulator uses replaceable o-rings as seats and seals. All o-rings and seals are replaceable or exchangeable for new or different elastomers. The o-rings for the intake and exhaust valves are set into a special grove that captures the o-ring but leaves it room to move slightly and seal correctly for positive shutoff. The QB3 incorporates an electronic pressure sensor that senses the downstream pressure at the work port for accurate regulation. The device accepts a zero to 10 V or four to 20 mA command signal and provides an analog output that corresponds to the actual pressure.