IP stands for 'Ingress Protection'. An IP number is used to specify the environmental protection of enclosures around electronic equipment. These ratings are determined by specific tests. Connectors may be susceptible to ingress of foreign materials such as moisture or dust, particularly in the unmated condition. Protection from this ingress is provided for connectors by the housing and the seal between the plug, jack and cable or between a jack and a panel. The IP standard rating system defines the degree of protection provided. The standard IEC 60529 has specified the degree of protection and divided it into several levels, defined by the IP number, which has the letters IP followed by two digits. The first digit defines the protection against the ingress of dust particles and the second digit defines the protection against the ingress of water. The table shown here shows IP ratings for electrical connectors. Amphenol RF connectors are rated IP67, and IP68 is available. IP68 is when a customer specifies what level of protection is required. A customer specification must be provided.