Pulling all the good bits of technology from it's big brother (SRAM XX1) the X01 derailleur offers serious punch at a more budget concious price. Sporting the same genius X-HORIZON parrallelogram design to eliminate ghost shifting and ROLLER BEARING CLUTCH to hold the chain tight an reduce chain slap.
The main differences between the XX1 and the X01 are:
Standard sealed bearings in the jockey wheel on X01, Ceramic Hybrid in the XX1.
Stainless steel pivoting hardware on X01 and Titanium on XX1.
Otherwise, they are the same units.
Weight is still super light at 250g.