For Sale(PA): Nitro regulator and auto gastank change over system

Hello all. I recently picked up this regulator and the attached device from an auction in hopes I can use the regulator(didn’t know it was nitro) but I can’t use the regulator and I don’t believe I will ever need a change over system.(I did get some other needed stuff)

I have a tap-rite dual gauge nitrogen regulator - 740n series
I have a “The eliminator” by Assurance Valve Systems.

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I am looking to get about 350$ for them.