Search sprinklerwarehouse.com
If that fails, and it might as that is a pretty random part, look in your yellow pages for irrigation supply houses....
Ewing Irrigation
Horizon Irrigation
Hughes Supply
John Deer Landscape
That failing, go to the watts website, and look for a distributor near you...I'm guessing you will have to order that part....
Good luck,
Sprinkler Solutions, Inc.
Arizona and Colorado
www.sprinklersolutions.net