These Pro Adapters allow you to convert the Speedline Carbon Forks ( and most other 20mm Carbon Forks ) to accept a traditional 3/8" ( 9mm ) female axle. These are the Pro Model of the Adapter that is a 2pc adapter that threads on to the 20mm fork to make the most stable connection with your fork and hub. These are machined from 7075 T-6 Aluminum, here in Apple Valley. Requires an 18mm thin open end and a 6mm Allen for Installation. Machined Silver Finish only.