The Shimano RX100 RD-A550 Rear Derailleur is a vintage road bike component designed for 7-speed bikes. Made of durable aluminum alloy, this rear derailleur features a short cage design for smooth gear changes. With a sleek silver color and Shimano branding, it is compatible with models 105 and is a perfect choice for road, racing, and touring bikes. Made in Japan, this rear derailleur is a reliable and high-quality addition to any cyclist's performance bike.