Kolk underground hydrants are made of ductile iron GJS-400/500 (DIN1693 GGG-40/50). Designed acc. to EN 14339, Kiwa BRL 614-2 or -4 with flange drilling acc. to EN 1092-2 (ISO 7005-2). Epoxy coated (Resicoat®) acc. to EN 14901 (DIN 30677-2) and GSK certified (RAL-GZ 662).