POWERTEC 70123V 4-Inch O.D. Splice, Black, 1 Pack

Needed to extend my vent hose on my Laser Engraver and this was an easy choice. Great price, solid item and a perfect fit! Does a great job.

Yes, this is a 2 1/4" I.D. coupler for 2 1/2" vacuum hoses, but the I.D. is off by 1/8", which is excessive for a friction fit coupler. It sits in my bag of unusable products. I have other POWERTEC products that are as advertised and work as expected, but this one seems to have missed quality control. For what is effectively a piece of plastic to connect two pipes, this product is excessively overpriced. Probably best to invest in a 3D printer to push this type of coupler out in a fraction of the cost, especially since I need several of these units. I may even post the 3D image so others can use it with their 3D printers.

Works and fits like they should with my dust collection setup

This works pretty good, but now I think 2" flexible rubber pipe coupler is even better, and can be adjusted to fit any brand, both new and old vac hoses. These hard plastic ones don't fit well on every brand.

Don't know why these are so hard to find. They often come in kits where they are needed but hard to find separately. That said, these appear to be fairly heavy duty. What cost them a star is that they fit loosely on my 2-1/4 inch hose. Easily addressed with a tape shim but a tighter fit would have been appreciated