Style: 20mm hubs.

>Hubs with a diameter of 20mm for added strength while riding DH or simply racing XC. 20mm forks can come as Thru Axle bolts or 20mm Quick Release.

Style: 9mm Q/R hubs.

>Hub that accepts 9mm Quick Release skewers to attach the wheel to the fork. This is the traditional style found
on most  XC and Road wheelsets and forks.

Style: 20mm/Quick Release convertible.

>A hub that allows use of a 9mm Quick Release skewer or an adapter that converts it to a 20mm Thru Axle. There are no adapters that can convert 20mm fork to 9mm Quick Release.