AWV - Administratie Wegen en Verkeer - Roads and Traffic Administration AKSESS 400 - The trademark name of a cover type in the manufacturer PAm
The lid is similar to another cap of the same manufacturer of a similar brand
GS - Spheroidal graphite cast iron - a special cast iron in which the crystallization of carbon has been slowed down, which makes it close to steel - also called ductile iron (Thanks to Vuori Susi for the clarification)