I bought one of Bob Leonard's Frugal Vacuum chucks a couple of years ago and just love it. It came with a PVC 4" Sewer and Drain coupler for the chuck but I made a new one (actually 3: 2", 3" and 4") from schedule 40 PVC couplers and applied Rubber Chucky bumpers for cushions. This works very well. The bumpers don't wear like closed cell foamies and they leave no marks. Highly recommended.