The lid is similar to another manhole cover made by the same manufacturer
GJS-500-7 also called GGG50 marks a strong and heat-resistant type of metal while GJS is a sign for Continuously Cast Spheroidal Graphite Iron - which describes a process in which the metal is continuously fed.
Fors A/S provides water, sewage, waste and heating services to the cities of Holbæk, Lejre and Roskilde.