Dia-Compe front brake recessed nut for freestyle.
This is the type nut needed for forks that have a recessed bolt hole so that the brake can be mounted flush (so that there is not a nut to interfere with freestyle tricks). This type of recessed nut is also used on other types of bikes.
Size: M6 X 1.0 X 15mm (overall length)
Head diameter: 10mm
Shaft diameter: 8mm