Shimano XTR FD-M986-D Direct Mount Front Derailleur - Double $99.95
Shimano's Direct Mount XTR FD-M986-D Double makes derailleur setup about as easy as it can possibly be. This XTR Dyna-Sys Direct Mount Front Derailleur is a traditional-styled (bottom swing) front derailleur that's nearly identical to the clamp-on M986 — save for the lack of a clamp.
Instead, this derailleur has a flat surface with an upright rib on the back that corresponds to the groove in the flat Direct Mount you'll find on compatible frames. One bolt holds it all together and your only adjustment will be up and down in relation to the chainrings. Since there's no way to twist the derailleur around the seat tube, it goes on lined up perfectly with the chainrings, and shifting should be spot-on once the cable tension and limit screws are set.
The Shimano XTR Direct Mount Double Front Derailleur FD-M986 is specifically designed for use with Shimano's XTR Race Double Crankset and XTR 10-speed HG-X chain, and the maximum chainring size is 42 teeth. The big difference between this derailleur and the triple-compatible version is that this one has a shorter cage. Using it with an XTR triple crank would result in the chain dragging across the bridge at the bottom of the cage when using the small ring. It can be used with top- or bottom-pull cable routing.