All-Parts Knobs, Water Buffalo Horn, Pair

Water Buffalo Horn Knobs (Qty 2). Includes set screw. Black with white flecks, rounded dome top. Each knob is unique.

Hole diameter designed for the solid shaft pots found (usually) in import guitars with metric shafts. 

These holes are too small for solid, USA CTS style pots, which have 6.35mm (1/4″) shafts.  The holes are 6.0mm in diameter.

If you need an intro on the difference between split shaft pots/knobs and solid shaft pots/knobs, have a look at the photos.
The split shaft is on the left, it has a slot in the shaft, and the shaft is splined. These knobs just push on and tension keeps them in place.
The solid shaft is on the right, and it is smooth and round. No splines. The knob on this stays in place with a set screw.