Willis Supply, a subsidiary of Willis Supply of Knoxville, opened its office at 801 East Main Street in 1960.  Its manager was Manford Willis, a native of Kingsport.  The company wholesaled electrical, plumbing and boating supplies.

This is plastic specialty piece that fitted over the dial of your rotary phone.

It has what look like three badly placed thin pieces of paperboard on the back, perhaps there to stabilize the piece. The notch in the lower right accommodated the finger stop (actual name).
I haven’t been able to determine when this company closed, but this item would have been pretty much outdated by the mid-1960s, as the  push button phones took over.

In a 1968 ad supplement to the Kingsport Times-News, this company bragged of “Selling GOOD Products in the Best DAMMED Valley in the World”.

Remember the dial tone?