Rectangular Ducting Round to Straight Offset Adaptor Part Number: 110x54mm Round to Rectangular Adapter – A110100 204x60mm Round to Rectangular Adapter – A204125 220x90mm Round to Rectangular Adapter – A220150 110x54 to 100 Offset Straight Adaptor – A110100 Used to connect 110x54mm ducting to 100mm round male fittings. A 100mm connector (C