Sprinkler line device.

What is the purpose of this device in sprinkler line ?

It appears to be a back flow preventer (anti siphon vacuum breaker).

You mean the device that says, “Champion VB 12362” ? :wink:

To protect against cross contamination.

http://www.irrigationdirect.com/irrigation-products-and-supplies/sprinkler-irrigation-repair-parts/champion-irrigation-repair-parts/champion-irrigation-262-362-repair-parts

http://lmgtfy.com/?q=Champion+VB+12362 :razz: