Shimano Slx Rear Derailleur Shadow M663 10 Speed

This is a tough, aggressive, yet light, low profile, 10 speed, SLX, mountain bike rear derailleur, that has a high image and covers All-Mountain riding.
It has Dyna-Sys components, a top normal design and a range of 11 - 36 tooth sprocket sizes and a total capacity of 42 teeth (SGS).
This also has many functions that are different than XT and Deore, such as a front double chainwheel as an option, which XT or Deore do not have.