This bike is just one of the antique racing bikes hanging on the wall of my neighbor Gian Bongiorno’s shop. It’s one of Campagnolo’s earliest shifting mechanisms. Apparently Fausto Coppi won the Tour on it. To operate it, you pull one lever to undo the axel quick release. At this point, the axel is imobilized in the dropouts only by notches in the dropout! Then you pedal backwards, using the other lever to change gears. Once the chain has moved to the new gear, you redo the QR for the axle, then pedal forward. Apparently these were popular because they were light weight, but they caused many accidents.