This is a U.S.A. made unused Seth Thomas Trademark Double end clock key, one side is for winding the clock up and the other is for adjusting the time.
This key will fit your antique Seth Thomas mantle or wall clock with #89 movements.
This key will not fit Seth Thomas clocks with German movements or Seth Thomas clocks that have 120, 124, or 125 stamped into the back plate of the movement. Seth Thomas clocks with German movements in them need my Hermle #7 key, and clocks that have movements stamped 120, 124, or 125 need my Seth Thomas #4/0000 key.
This key is a #6/0000
This key is American scale.
Check out our key size chart.