I just put a cnc router at the end of my nordfab run. The 8" Pipe stops way above where I can reach at about 10'. Then the hose attaches to that and runs to my shoe from the above center ofy table. I could have made a plug/stopper to slip in the shoe, or installed a blast gate in line on the hose, but i did not want to lessen the hose integrity since it moves a lot. I then thought why not use the rare earth magnets kent has in the shoe aleady and have him make me a spacer with no hole cut for the dust hose. Basiclly a quick connect cap. Seems like a slick idea for a block. I ordered it today. In reality this collector uas enough suction, even with two other 8" ports open, to use it as is for cnc routing, so having one 4" open would be nothing. Still I like to seal off lines i am not using. Any more to come when it arrives.