Vittoria Margherita bicycle rear derailleur mechanism - never installed in excellent condition. All components included except a small chain stay mount to locate the rod near the bottom bracket. Loosen the chain tensioner by moving the handle forward in the toothed guide. Pedal backwards and at the same time rotate the triangular head of the handle.
This causes the rear paddles to push the chain across the sprockets either in toward or away from the hub to the desired sprocket. Re-tension the chain by pulling the handle back and engaging the teeth. These mechanisms were used with? Chains and 3 speed cassette's.Used from mid 1930's in to the 40's.