The Global Maritime Distress Safety System (GMDSS) is a set of international regulations for the safety of life at sea. The system includes a number of individual components, such as the Global Maritime Organization, which sets standards and monitors compliance with GMDSS regulations, and the International Telecommunication Union (ITU), which provides a single worldwide radio frequency band for distress. The ITU has allocated frequencies in the very high frequency band (VHF) for use by ship stations transmitting distress calls and messages. These are known as "Maritime Mobile Service" channels, or MMS channels. GMDSS also requires all ships to carry an Emergency Position Indicating Radio Beacon (EPIRB) or Personal Locator Beacon (PLB).