Surly Shimano/SRAM 8/9/10; Shimano Dynasys 11 40 Hole Bicycle Rear Hubs
About Surly - Surly is a leading manufacturer of bicycle frames, and was one of the first Fat Bike manufacturers.
The cassette body type is the type of cassette and number of speeds the hub will accept.
The hub drilling is the number of spoke holes. It must match your rim spoke count.