DIN 19571-2
DIN 19571-2 Gully tops 500 × 500 for gullies, class C 250, curve type - Particulars
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/1997
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/1997