This shoe has the same dimensions as the 18-166 except that the top is is 7/8" thick instead of 1/2" thick, and the bottom is 7/16" thick instead of 5/16" thick.
Please tell me if the 18-166 will work since it is the one that is closest to mine.
Tom from SWISCO responded:
November 23, 2011
Unfortunately, the 18-166 Kinco Top Sash Guide is the closest possible replacement for your sample that we can offer at this time. If you wish, you can browse through our Top Sash Channel Balance Guides Catalogue to see if you think there is anything else that would work for your application.