Shimano Ultegra 8 Speed Bar-end Shifters LD801 $84.95
These permit switching between indexed and friction shifting.
Complete with cables, housing and down-tube cable stops for attachment to down-tube braze-ons. If your bike doesn't have the braze-ons, you also need to buy a pair of clamp-on cable stops.
The 7-speed units are no longer available, but the 8-speed shifters actually work quite well with 7-speed cassettes, especially with modern rear derailers.
It works for me and a lot of other people.