Luminaires need to be designed to minimize the risk of penetration by solid foreign bodies and moisture. The degree of protection provided is indicated by an IP code ("Ingress Protection") made up of two numerals (see "Degrees of protection" table). The first numeral (1 to 6) indicates the degree of protection against solid foreign bodies, the second (1 to 8) the degree of waterproofness. Higher degrees of protection include those lower down the scale. Where one of the two numerals is missing, its place is taken by a capital "X", which means "untested".