Three gauges in one! Prosport cleverly used the real estate left empty in other A/F gauges to give you a blue LED digital volt meter AND and LED-sweep air/fuel meter in one gauge. The center digital display (which is available in blue or amber) gives you your electrical system voltage. The outer ring of LED's gives air/fuel ratio. (Hook it to the rear one-volt oxygen sensor in your Subaru.)
But wait, there's more! This gauge can function as a display for any standard five-volt WIDEBAND air/fuel meter, like Innovate, AEM, or PLX Devices. Just flip the switch on the back, and it'll use the wideband controller's output to display wideband air/fuel ratio. (This gauge is NOT a stand-alone wideband, though!) The gauge performs an "opening ceremony" self-test when the power turns on, too. 52mm gauge size. Includes mounting hardware and instructions.