Stainless Steel Check Valved Ball Lock Disconnect

[catman]

I’m planning out my keg system and in reading around I’ve become very worried about backflow into the gas line. I’d like to have stainless steel disconnects, and for the gas disconnect to be check valved, but I’ve only been able to find disconnects that are either steel or check valved, but not both. Does anyone have any tips?

Relatedly, both the regulator and distributor I’m getting are check valved. Is a check valved disconnect overkill?

Thanks!