American Shifter ASCAD18 Custom Shift Knob Adapter (12mm x 1.75 to 16mm x 1.5 Custom Shift Knob Adapter) Feature: 1- 16mm x 1.5 to 12mm x 1.75 Adapter Jam Nuts: Included Material: Billet Aluminum Packaging: Single Sided Blister Feature: Protective coating reduces wear