POWERTEC 70136 4-Inch to 2-1/2-Inch Cone Reducer Connect 4 ID flexible dust collection hose to 2-1/2 ID flexible dust collection hose 4 nominal OD end measures 3-61/64 OD and 3-41/64 ID; 2-1/2 nominal OD end measures 2-15/32 OD and 2-9/32 ID Adaptable to most shop vacuum cleaner hoses with 2-1/4 OD connectors Use Powertec 70149, Dust Control Flex Cuff (sold separately) to connect 4 nominal OD end to other 4 OD adapters; Use Powertec 70148, Dust Control Flex Cuff (sold separately) to connect 2-1/2 nominal OD end to other 2-1/2 OD adapters Tough durable ABS plastic