Shimano Alivio RD-M3100 Shadow 9 Speed Rear Derailleur Colour:Charcoal the MXR 20 bridges the

the MXR 20 bridges the gap between 18" and 20" wheel sizes - meaning you can get him onto bigger wheels earlier and keep him there longer

S2 Industrial Tool Steel

130mm trail bikes

SRAM and all other12 speed drivetrains

Shimano Alivio RD-M3100 Shadow 9 Speed Rear Derailleur Colour:Charcoal the MXR 20 bridges theAbout Shimano Alivio RD M3100 Shadow 9 Speed Rear DerailleurThe SHIMANO ALIVIO M3100 rear derailleur delivers a low profile design that lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design. FeaturesLow profile design Total capacity: 45T Max. low sprocket: 36T Adjustment barrel SpecificationsModel No: RD M3100 SGS Series: SHIMANO ALIVIO M3100 Series Compatible Chain: CN HG53 9 speed Total Capacity: 45T B Axle Hollow