Suntour Cyclone Mark 2 rear derailleur! The model # 3500 was Introduced in 1981 in response to Shimano’s Dura Ace AX. The previous generation of cyclone of intricate details and sculpting were gone in favor of a more modern, sleek, and aerodynamic approach.

This is a beautiful NOS derailleur! Weighing 164g, maximum COG of 26 (or 30 if your hanger is 32mm) this NOS derailleur is in excellent shape and with a history influenced in an era of suntour/shimano competition