Area 419 Defiance Finger Groove Bolt Knob and Area 419 Steel 5/16×24 Bolt Knob Adapter

Bolt knob is 17-4 Hardened Steel, Black Nitride with

Knob adapter has slight marring (see in pic) - priced accordingly ($65) for Bolt knob and Adapter.

Not sold seperately

However-

Also for sale is a seperate Area 419 Steel 5/16×24 Bolt Knob Adapter ($35) 

(Mint condition. Will fit Seekins Precision bolts among others).