They used to be made by Granite State. They used Super Coverite and sewed the hinge line. I only have a few left so I started making new ones with scraps left over from Super Coverite covering jobs. I don't see the dyed colors in Coverite advertized anymore. Tower has white and antique still available.
I love the limp gapless hinge line especially on thin surfaces. I don't like the added thickness under a film covering job.