2 THUMBIES UP FOR PAUL COMPONENTS!
I have a fresh one from Paul Components -- Easily transform bar end shifters into thumb "top-mount" shifters. The Microshift Thumbies by Paul Components bring back the thumb shifting from the earliest days of mountain bikes through the late 80s, which, by many opinions makes shifting more precise and smoother; a much better feel than trigger or twist shifters. Microshift bar ends are the only shifters compatible with current Shimano MTB drivetrains and come stock on many drop bar "adventure" bikes. This simple hack allows these bikes to be set up flat bar, providing the rider with more options.
The Thumbies feature a clamp for an easy installation, comes in 22.2mm (7/8"), and is raised up to give clearance for hydraulic brake levers. The Thumbies weigh in at 60g and are made of 6061 Aluminum with options of anodized or polished finish.
Microshift compatible, shifters are not included but are readily available in 8 through 11-speed versions, and many have an option for friction-shifting.
MSRP: $42 single / $79 Pair