I have a pair of used thumb shifters. They came off of my Clem Smith Jr. "L" bike, which is gear as a 2x9. Personally, I do not care for them. I switched them out and I installed a pair of Suntour BARCON ratchet bar end shifters from my parts drawer.
The shifters are from different manufacturers. One of the shifters for the rear derailleurs has a scuff mark at the end of the lever. They both functioned well prior to removal on my nine cogged cassette.
$50.00, shipped in the CONUS
Thank-you for your interest,
Kim Hetzel
Yelm, WA.