You are looking at a very gently handled 3" button from the 2011

Western Minnesota Steam Threshers Reunion

in Rollag, Minnesota.  This pin is in excellent condition with no visible wear.  Features a photo of an antique Avery tractor and reads:

 

WESTERN MINNESOTA STEAM THRESHERS REUNION

Avery Expo

Sept 2-5, 2011

ROLLAG, MN