Review on Black Flexible PVC Coupling with Stainless Steel Clamps by Supply Giant - 1-1/2 Inch by Steven Murray

The item I was holding is advertised and marked 1 1/2" but the actual inside diameter = almost 1 7/8" and the outside diameter = 2 3/8". A supply giant must have a giant ruler! Update August 31, 2020: I subsequently purchased a 11/2" coupler from Home Depot, thinking it would be the right one from a trusted supplier for DIY repairs, and it was from a different manufacturer. it was 1 7/8" ID too! I'm not a plumber, maybe it can or should be tightened to 1 1/2 inches? I don't know, haven't tried it since I'm using the same 1 1/2 inch connector that Home Depot ordered, just in case I'm at this point on anything to do with shipping etc. also bought a 1 1/4 inch connector. (actual ID = 1.5 inches) and this works for me, I use it to install a 1 1/2 inch Snappy Trap under the sink. So now I reserve the right to judge as I may not know the coupler size specs, going to 3 stars and suggesting you maybe try more than one size, which is common for me and the plumber anyway! Update 09/04/2020: I have changed to five stars as I now think the size for PVC pipe should be 1 1/2 inch ID and as the PVC pipe is heavy walled you will need a coupler, which is marked for 1.5 inch diameter PVC pipe with an ID of 1 7/8. Customs service. In this case, the only way for the manufacturer to avoid the confusion is through a lengthy analysis, which in any case causes confusion. My non-professional conclusion is that they appear to be PVC connectors which if marked 1.5" have an ID of 1 7/8" and those marked 1.25" have an ID of 1, have 5 inches. They're not just for PVC pipe, but finding the right size can be tricky.