For different coffee brewing methods you need different size of coffee particles. It is important to get the best taste possible. 

There are 7 grind sizes.

Extra Coarse (10)

Looks like peppercorns. Mostly used for Cold Brew.

Extra course grind

Coarse (8-9)

It is similar to coarse sea salt. It is ideal for French Press, Percolator or coffee cupping.

Coarse grind

Medium Coarse (6-7)

Looks like rough sand. Perfect for Chemex. 

Medium coarse grind

Medium (5)

Similar to sand consistency. Acceptable for AeroPress and Siphon.

Medium grind

Medium Fine (3-4)

Looks like table salt. Also good for and for pour over coffee drippers.

Medium fine grind

Fine (2)

Finer than table salt. It is ideal for Espresso Machine and Moka Pot or even AeroPress. 

Fine grind

Extra Fine (1)

Looks like cocoa powder. Turkish and Greek coffee.

Extra fine grind