For Sale is a brand new McCulloch sprocket as shown in photo.  It is for the 1/4" pitch chain. 

This fits:
McCulloch Mini Mac 25, 30 and 35

McCulloch Power Mac 6, PM6A, and Mini Mac 6

This is "NEW OLD STOCK" meaning it has been on the shelf for 20+ years, does not have a package, may have a spot or two of rust on it, but it is in perfect unused working condition.