Ducting

Kair Rotating Elbow Bend Adaptor 204mm x 60mm to 100mm - 4 inch Rectangular to Round 90 Degree Bend Adapter

Flat Plastic Ducting to Round Angled Transformer 220x90 - 150mm

Radial Ducting Plenum with 2 x 75mm Connections, Pack of 2 - Best Value.

Radial Ducting Plenum with 2 x 75mm Connections

Kair Rotating Elbow Bend Adaptor 204mm x 60mm to 125mm - 5 inch Rectangular to Round 90 Degree Bend Adapter

I-sells Metal Ducting 90 Degree Bend 125mm / 5 inch with Rubber Seal

Kair Rotating Elbow Bend Adaptor 204mm x 60mm to 150mm - 6 inch Rectangular to Round 90 Degree Bend Adapter

Flat Plastic Ducting to Round Angled Transformer 220x90 - 125mm