This is a wideband O2 controller. It's the APSX D1G1 WBO2 controller. APSX D1 G1 Wideband AFR Controller It has both analog and digital outputs, as well as a simulated narrowband output, should a user wish to configure it that way...the only reason I see the simulated NB output being useful is if it's hooked to a tuner that isn't WB capable. The analog WB output is a 0-5VDC sweep that I'll wire directly to my ECM, and the digital output will be wired to the digital display that came with the kit. The cool thing (I think, anyway) about the digital output is it is a 9600 baud 8N1 that can be connected to a PC, if you didn't purchase the kit with the digital display...seeing as it was a $5 adder for the digital display, I just went with it. I'll likely gut an old gauge housing (trying not to make it look hacked, of course) and see if I can mount that in the dash for an A/F ratio display. Not that it's completely necessary to have that flashing in my face all the time, but it could be useful should something go awry.