Product review (1 stars): Did not fit 4 inch duct
The sleeve that is supposed to slide into the duct from the dryer vent did NOT fit. I bought a decent dryer vent that has a fairly heavy gauge 4 in duct (i.e. doesn't really flex). The sleeve would not slide into the duct. I even tried sanding the sleeve to try and reduce the diameter and it still wouldn't fit. (Unfortunately, since I tried to modify it I assume it can't be returned.) I bought a connector at Home Depot that appears to be the same as the Dundas Jafine connnector sold on Amazon, and it worked fine.