The first photo is a back flow device, either a dbl check valve or an actual backflow device. Most of the time this seen in comerical buildings but more and more they are going to be seen in residential city water systems. These are used to prevent the back flow of water and any contaminates the water lines can pick up, from going back into the city water system. We are seeing more and more of these or some type of anti backflow valve on residential houses. You see more and more people watering their lawns with a canister attached to the hose to provide some type of fertilizer or help grow agents. With out a backflow there "could" be a possiable back feed from the city water system bringing in the chemicals into the main water system.
I am not sure what the 2nd photo is by the picture.
Hope this helps.

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Well thats my 2 cents.
Brian Kelly
Kelly Home Inspections