Includes:

Adapter, CNC polished 505215
160mm disc brake rotor 6 bolt pattern 505217
6 rotor mount screws
2 caliper screws with washers

Applications:

Adapter 505215 is designed to thread onto a standard free wheel hub  - view
Convert a standard free wheel into a front disk brake wheel - video
Example triple tree chopper fork -  view
Example springer fork - video

Thread the adapter 505215 onto a free wheel; bolt 160mm rotor 505217 to the adapter with the 6 screws; place the wheel on the left fork leg with the caliper.  
Important instructions (warning): Use thread locking glue between the hub and adapter and all other screws included. Use Loctite Threadlocker Red 271 High Strength, or equivalent glue.