Product review (2 stars): Not as pictured!
The pictures of this product are not accurate. If you need a duct that has the crimped end to fit inside of another peice of duct do not buy this item. Look at the picture with the box - the image on the box itself shows that this is simply a semi-rigid four inch diameter duct with two clamps included. As a long-time Amazon customer (~15 years) I've come to trust their pictures but that was a big mistake on this one.
I'm giving this two stars only because the product itself appears to be of good quality.