The Alivio CS-HG51 cassette is designed for 8-speed drivetrains. The cassette features profiled sprockets for smoother shifting. Ideal for MTB bikes, it also performs well on trekking bikes. Key information: Made of steel Drilling holes to reduce weight Contoured elements enable faster gear changes Hyperglide sprockets ensure smooth operation Most of the sprockets are integrated into the spider for increased stiffness Removable smallest sprocket Nickel-plated surface for increased durability Lockring made of highly corrosion-resistant steel 11-13-15-17-19-21-24-28 silver color 8 rows