The Shimano Tourney RD-TY300-SGS Rear Derailleur is a reliable and affordable component designed for entry-level mountain bikes and hybrid bicycles equipped with 6 or 7-speed drivetrains. This direct mount derailleur features a long cage, a total capacity of 43 teeth, and compatibility with HG-UG 6 or 7-speed chains, making it suitable for a wide range of gearing options.