Not to be confused with a fork conversion kit, this simple adapter will convert any 15x110 Boost hub to 12x110 Boost to fit your Focus Atlas fork.
Adapter is shown with 2x 15 mm ID x 5 mm ID spacers sold separately. Combine this hub adapter with those spacers plus a disc rotor spacer to mount a 15x100 hub in a 12x110 Boost fork. See related products below.
Note that some MTB hubs may have 21 mm diameter end caps which may not fit certain 12x110 forks which have been designed for only 19 mm diameter end caps. Please measure both the fork and hub to confirm before ordering (reference images above for how to measure).