For the late 1980s the Bridgestone Klimatic got a major make-over. The basic design now incorporated SunTour's signature, and excellent, dropped and slanted parallelogram. Finally this looked a very good device, but by this time Shimano had established SIS as the de-facto standard, and no one (except Bridgestone) was interested in a cam based system.
Interestingly the indexing mechanism means that the adjustment screws have been moved to the front of the derailleur (as on the original SunTour Competition). Long ago this design was abandoned because the screws tended to catch spray from the front wheel and rust solid.
This is a well-rusted example of an early long cage 'GTL' version, with SunTour's final design of double pivot cage. Unlike SunTour's earlier attempts at double pivot cages, I found this final iteration to be reliable and extremely effective.