Double line vacuum brake check valve

[Kershaw]

Is this an ix thing? Why have one pull pre throttle and one post?

[nando]

I don't know. Some of them came with one and some came with two and the other is blocked off. The ix booster is different so maybe it works better with 2 lines?

[Kershaw]

I ended up using a Dorman BMW/GM universal part. One in, one out. It was $5 at autozone. I opened up one of the gaskets it came with and plugged it straight into the booster. Works great. Brakes don't feel any different and it simplified my ITB vacuum routing.