Inner coupling 90. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

Reducer DN75/DN90. DN75 refers to 75 mm outside / 63 mm inside diameter; DN90 refers to 90 mm outside / 75 mm inside diameter.

Duct Flexi Coupling DN90. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

External DN90 connector with bracket. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

Short DN90 duct reducer. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

Long DN90 duct reducer. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

Reducer 2xDN90/1xDN50 – Geberit. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.

Reducer to flat pipe DN90. DN90 refers to the 90 mm outside duct diameter; the inside diameter is 75 mm.