Some people like to use PVC drain pipe in their dust collection systems and this adapter fits over the standard 4" drain pipe outer diameter of 4.215" and converts to a 4.00" outer diameter for use for 4" flex hose.
The pictures demonstrate how this adapter is used with flex hose in conjunction with standard Magport and Blast Gate units.
Also pictured is how the standard 4" Magport unit fits within the 4" drain pipe leaving only a minimal space and can be used this way as well.
