NilfiskCFM 118 Industrial Vacuum Cleaner 50mm Inlet to 40mm Hose Diameter Reducer
NilfiskCFM Inlet 50-40 CFM Iron Reducer, so the NilfiskCFM 118 industrial vacuum cleaner for example, can use the 40mm hoses.
In the picture, it's SIMILAR to the lower part, the ridge on the Right Hand Side, is INTERNAL not external as photographed. A 40mm hose is connected to it via a 40mm rubber or plastic cuff.
PLEASE NOTE: The parts above ARE reducers from the container, whilst this part pictured, enables 40mm accessories to be used on 50mm hoses.
At the moment, as postage is capped at a maximum of $20, maximise the saving on postage and buy some of the related parts below, such as dustbags and a new hose, or a new floor tool and some other accessory!