Includes:

Adapter, CNC polished 505215 video
Disc brake rotor size 160mm  505217

Front hand brake lever  505208
Brake cable 65"  505212

Disc brake caliper for 160mm rotor  505203

Applications:
Ad a disc brake to a triple tree chopper fork or rigid fork.
Example on a triple tree chopper fork
Example on a 26" cruiser rigid forks

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.