4-1/2" To 3-7/8" Dust Collection Hose Adaptor By Peachtree Woodworking - PW425 4-1/2" To 3-7/8" Dust Collection Hose Adaptor Appx. OD on small end 3"-7/8" x OD on large end 4"-1/2". please check o.d size of PVC to make sure fitting will work Hose clamps are required for this type of connection. Used to connect your dust collection line to your 4" dust collection hose.