SNPWG was tasked by HSSC4 to provide an estimate of the number of potential Product Specifications related to nautical publications. At HSSC5 SNPWG reported their plans to develop altogether seven such specifications, one of which was named Navigational Services. Navigational Services has been assigned the number S-125, and was initially to include additional information regarding Aids to Navigation, AIS Aids to Navigation (V-AIS) and GNSSstations. Since then, the concept of S-125 has evolved and is today comprehended primarily as an extended substitute of the conventional List of Lights. S-125 would include, but not be limited to, the data normally included in a List of Lights.