Photo submitted by Brian Kavanaugh, “Attached is a pic of the left-side front thumbshifter on my well-thrashed and still much-loved 1985 Schwinn Sierra. What model shifter is this? Its original right-side companion was destroyed in a trail mishap involving a tree back in ’86 and was replaced at the time with a new-fangled SIS-style thumb shifter. I’d like to find a replacement to restore the cockpit’s original symmetry, plus I love the ratchet-style shifting action. I haven’t been able to find any images or info about this shifter. Other than the words “Shimano” and “Unishift Control” on the top ring, there are no markings anywhere on the housing.”

Readers, any help with this? More pictures after the break.