A quick learner says:
March 21, 2016
The balance top is black, the top part measures 14/16ths by 1/2 inch. The length is 1 and 2/16ths inch.
Paul from SWISCO responded:
March 24, 2016
Thanks for posting. Please see our 18-174 top sash guide and compare our dimensions to yours. This may work as a replacement.