The Shimano 105 RD-5800-GS is a medium cage rear derailleur designed for 11-speed Shimano road drivetrains. Its aluminum alloy construction offers reliable durability and a reasonable weight, while the wide link design increases rigidity and ensures consistent shifting across the cassette. The RD-5800-GS is built for riders who want dependable performance in varied terrain, as it can handle cassettes up to 32 teeth, making it suitable for mixed hills and flats or riders who need a bit more gear range for loaded touring or commuting. This model is compatible with Shimano 11-speed road shifters and is hanger mounted, which is standard for most road bikes.