I bought SunRace 6-Speed Clamp-on Downtube Shifters (28.6mm Clamp Size) with housing stops @ eBikeStop.com 6 years ago to replace my bar-end shifters. I had to improvise a new mount because the frame had cable stops (and my frame is too thick for the mounting clamp they come with) at the mounting point but that was cheap and easy. I still use them.