Insert "King"-related pun here.
We could use this intro paragraph to rave on about the all-around amazingness of basically anything and everything Chris King makes, but since you're already doing yourself the favor of looking up his hubs, we can probably spare you the rant. What you can't spare, however, is the Chris King ISO XD 12x142mm Rear Hub if you're building up a mountain bike with 142mm rear spacing and a SRAM 1x11 drivetrain. This hub is specifically designed for such a machine.
The technical superiority of Chris King's hubs — especially the rear hubs — is evident across all four dimensions of reality. In the first three, we start by observing the outside. In any color, King hubs look fantastic, with beautiful machining and finishing. The company's quality and consistency control are so stringent that entire batches of hub shells have been sent back to be melted down again if their anodizing is off by even one shade of hue. All King hubs' bearings are made in house and far exceed the precision and quality standards of competitors, on top of living within a legendary "all conditions" sealing system that is the same for its road hubs all the way up to its burliest mountain hubs — it's just that good — which leads us to that fourth dimension: time. King hubs last, and last, and last, and last.
But there's more to the inside story here. King's RingDrive freehub body engagement system is half of what makes the company's rear hubs so fantastic. The freehub uses a 24-pawl system to engage 72 (yes, a seven then a two) teeth within the hub, meaning that engagement is absolutely instantaneous when you put power to the pedals — no more of that floaty feeling that leads to a slamming of the pedals when you go to put the power down after coasting or when traversing tricky terrain. It means far greater control and response for single-speeding or trials-type riding, as well, not to mention that hallmark "angry bees" sound when coasting. And fear not for the frailty of what you probably calculate are tiny pawls and teeth, with all those numbers jammed into that freehub body, because King rear hubs can handle up to 800 ft/lbs of torque. Figure that world-class track sprinters are capable of putting out up to around 150 ft/lbs of torque at their peaks for only a few seconds. And yes, the axles, flanges, and every other part of the hub is at least that strong, making them more than tough enough for the gnarliest trails and biggest hits you can muster.
The Chris King ISO XD 12x142mm Rear Hub comes with a freehub body specific to SRAM XD drivetrains (XX1, X01, and X1) only. It has an ISO (6-bolt) pattern for disc brake rotors and can only be installed on bikes that use a 12x142mm rear thru-axle. It comes in three colors: Black, Silver, and Red.