Where do I hook up an A/F gauge on an Integra LS?

My friend has one and is asking me. I haven't looked at it yet, but he says there's a plastic cover over all his wires and stuff... I have mine spliced into the wire right off the O2 sensor, but he doesn't want to do that. Either way, which wire do I hook the signal wire off the gauge to?

Nevermind, got it. It goes on a solid white wire off the ecu.