Shimano GRX RD-RX400 10-Speed Rear Derailleur Size_700x18c The Crossmark II improves on

The Crossmark II improves on the speed of its predecessor while improving grip in intermediate conditions

and downhill specs

4 in or 7

142grams per calliper they offer a substantial weight saving

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Shimano GRX RD-RX400 10-Speed Rear Derailleur Size_700x18c The Crossmark II improves onSHIMANO GRX Rear Derailleur 10 speed RD RX400 SHIMANO GRX Rear Derailleur SHIMANO SHADOW RD+ 10 speed With an integrated chain stabilizer mechanism, the SHIMANO GRX derailleur provides a quieter experience and shifting security and precision on mixed terrain. For rides on smooth surfaces, the derailleur features and ON OFF switch for the chain tensioner. FEATURES Silent and uninterrupted rear shifting on rough terrain Adjustable chain stabilizer