Ball bearing/spring assembly in 1/4" NPT propane fitting

[travelingjw]

The enclosed photo shows the parts that came out of my propane hose that connects to the auto change propane regulator. I don't know which side of the spring the ball bearing belongs on. I also wonder if these are part of every propane hose for an RV.

[Isaac-1]

My guess is that this is a check valve setup to prevent higher pressure from the "full" tank from back flowing into the empty one after the switch over. If this is correct you would want the spring between the tank and the ball. But again this is just a guess. It could also be an excess flow preventer, which would be the other way around.