Bargain 12 mm Thru x 142 mm 32 Hole Center-Lock Disc SRAM XD 11-Speed Bicycle Rear Hubs
This is hub spacing and is the width of the hub. It must match your frame specifications.
The hub drilling is the number of spoke holes. It must match your rim spoke count.
This should correspond to the type of brakes you have on the bike.
The cassette body type is the type of cassette and number of speeds the hub will accept.