Use one spice mill with salt and the other with pepper or with different types of pepper and spice mixes. When you see through the glass that the contents are starting to run out, you simply unscrew the cap and refill. 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. When you want to clean it thoroughly, the top's cap can be folded up. The brown glass reduces the effect of daylight on the spices and makes them retain their flavour for longer.