DIN 16966-5
DIN 16966-5 Glass fibre reinforced polyester resin (UP-GF) pipe fittings and joints; Reducers, Dimensions
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/1982
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/1982