Need help to identify this WASHINGTON NATIONAL pinback!

[SPARK929]

Would like to sell this pin back but like to know the origin and year it came out and if there were any other teams produced.
Your help appreciated! Hope photo comes out!
It's for sell just make a fair offer.
Please contact me: spark929@yahoo.com
JOE
http://i1122.photobucket.com/albums/l534/spark9291/Scan_20171104.jpg (http://s1122.photobucket.com/user/spark9291/media/Scan_20171104.jpg.html)

[icollectDCsports]

Mid-1950s and from a set issued for pretty much every team, I think. Fairly common, and there are usually a couple of these available on eBay at any given time. Although they can be listed for more, I think a realistic sales price, depending on condition of course, is around $10. The photo in your post is small, but seems to show some scratches.