Cutoff valve replaced

[Jose Torres]

I was incapacitated from a recent surgery and had someone come and replace a broken ball valve on my system. I wasn't able to check their work at the time. Now I find they replaced broken valve with PVC one. Not going to deal with complaining to them. Didn't charge much. I'm more mobile now and will replace it myself. The question I have is what is the item in picture after the valve. Wasn't sure if it's a backflow preventer or not. Thanks for any help.

 

[Terry]

The brass valve has been there a long, long time.
Maybe a back flow or perhaps a pressure reducer. Sometimes they are marked on the body.

If it's on the irrigation system, I'm guessing backflow device.