Use one spice mill with salt and the other with pepper or with different types of pepper and spice mixes.
The grinder sits on the top of the spice mill, which means you avoid having spice residues on the table, worktop or spice rack.
You decide how finely you want to grind the contents with a setting on the top of the spice mill.
Has a porcelain grinding mechanism which is harder and more durable than steel grinders.