Got some in today that I had ordered to try. Fresh out the box I cut one open to see. the felt ends are glued on and not attached very well. The black cap ends are solid plastic with the filter media glued to them. These ends were on very well as I was not able to pry them off by hand. The glue job on the end caps is a bit messy. Here's some pics
FWIW, I have run a couple of these VIGOR filters in my Tundra and Prius with no issues. Inspection after changed showed nothing for me to be concerned about.