From Manufacturer's Website:

Teff (Tef, T'ef) Flour is a pleasingly light, uniquely flavored, whole grain flour. Due to Teff?s size, it is almost impossible to grind in your home mill. We are glad to do the work for you! Ethiopians make a flat crepe-like bread called injera from teff flour. Substitute teff for about a fourth of the all-purpose flour called for in your favorite baked goods recipe to add an appealing taste and added nutrition.