I've had the displeasure of taking one apart. It was wrinkled in the corners because there is no way to re-tension them or put a decent amount of tension in the first place. They look quick and easy for production shops, but only for totally disposable prints.
I made a couple of batches using this equipment a few years ago in sizes up to about 5’ on the long side. It was a test and the results are largely crap. The glue doesn’t get along with many canvas types and causes an odd pattern along the glue seam. Over time I predict it will wear oddly as the glue and double back tape ages differently and the work relaxes.
It also doesn’t do much of a job of tensioning the surface of the work. It might be okay for small works but is completely unacceptable for larger ones. The one part that ends up looking good is the corners.
This product is re-sold under several different names.