The mask consists of a black patch over one or both eyes (for the blue coat colour) or a red patch over one or both eyes (for the red coat colour). Depending on whether one or both eyes have a patch, these are called, respectively, 'single' (or 'half') mask and 'double' (or 'full') mask. Dogs without a mask are called plain-faced. Any of these are acceptable according to the breed standard. In conformation shows, even markings are preferred over uneven markings.