This Charnwood reducing cone is used for stepping down or up in hose size and for connecting a hose line to machinery with a different sized outlet. It is recommended that 100mm diameter hose is always used from the extractor to the dust producing machine and then the reducing cone fitted. Using any length of hose of less than 100mm diameter will reduce the performance of the extractor and should therefore be kept to a minimum. A 100mm hose clamp should be used to fasten the hose to the reducer. Outside Diameter: From 100mm to 38mm. Inside Diameter: From 93mm to 31mm. Overall Length: 170mm. Material: Plastic.