Inner coupling DN75. DN75 refers to the 75 mm outside duct diameter; the inside diameter is 63 mm.

External DN75 connector with bracket. DN75 refers to the 75 mm outside duct diameter; the inside diameter is 63 mm.

Short DN75 duct reducer. DN75 refers to the 75 mm outside duct diameter; the inside diameter is 63 mm.

Long DN75 duct reducer. DN75 refers to the 75 mm outside duct diameter; the inside diameter is 63 mm.

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