Cummins= the grey valve is 1 1/2". The actual valve is USUALLY reachable from under the black plastic cover under your rig. If you don't mind getting down low you can replace it with a pull handle just like you did with your black valve.
Go to any rv store and buy what ever brand they sell. The flanges on the pipes are a industry standard configuration for the bolt pattern.
Some claim that some valves are different. That may be true. Don't know why, because all of the flanges are the standard pattern.
Bill
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