Supply Giant 6I49x4 Flexible Coupling, 4 inch, Black

07/31/2021:Update: I'm currently rebuilding my dust collection system (removing old duct tape, replacing some hose with 4" pvc pipe and replacing connections with these couplers). I am thoroughly impressed with these couplers. With a little effort you can work these over the larger elbow/splitter end. You can use a flat head screw driver but a drill with a 8mm socket will be way faster for tightening. I have had to add additional ceiling strapping to hold up the additional pipe and because the rubber coupling are a heavier than tape. Be showing picture soon. 07/19/2021: Update: I change my rating because even though there is a lot of space between the couplings and a 4" pipe the rubber is flexible enough to really clamp down and hold air tight. I use all four of them and I am presently surprised. Ordered another set of 4. Disregard my previous rating. +++++++++++++++++++++++++++++++++++++++++++ This coupler is way bigger than 4" It is closer to 4.5" The pictures do show the inside diameter as 4.5"...my 'beef' is then why call them 4" couplers. My bad...an I'll eat this one, but it won't happen again!

I don’t feel it’s fair to give this product less than five stars, because it appears sturdy and as advertised, but it doesn’t meet my needs at all. I bought this to connect four-inch pvc (sewer) pipes and gates for a wood shop sawdust collection system, but these couplings are so oversized as to be unusable for this purpose. I can’t tighten them enough to form a proper seal; they bulge and deform too much.

I had to add a Y fitting and blast gates to my dust collection system. I find it difficult to find the exact fittings to cobble the system together - these flexible fittings make it a lot easier.

These are for 4” ABS pipe not 4” dust control how ever they show up in a search for dust control couplings

I purchased these because they were significantly cheaper than the PowerTec, Woodcraft and Rockler rubber couplers. Unfortunately, they are too wide for a standard 4" dust hose and 4" PVC pipe. They will work if you cinch down the straps but the couplers will then mushroom out. If you don't mind that the couplers look like fat rubber mushrooms they'll work, otherwise I would order the PowerTec rubber dust couplers instead.