Dust Collection 4" Threaded Quick Adapter By Peachtree Woodworking - PW421 Quickly connects your hose to a 4" O.D. fitting I.e., hoods, gates etc. 4" I.D. x 4" O.D. Also available is a 4" Quick Disconnect (Not Threaded, SOLD SEPARATELY) We also have a 4" to 2 1/2" Threaded Quick Adapter (SOLD SEPARATELY)