Type of heat-set tissue

I am unfamiliar with the roll version.They should both be fairly transparent. Also, the larger version is more useful for large areas. 

Thank you, I've just been searching for information about this subject for a long time and yours is the best I have came upon so far. But, what about the conclusion? Are you positive concerning the supply?

So the only place I have found the "sheets" is indeed Talas. I have purchased one sheet but not found a project that calls for that. The Neschen Filmoplast R Heat-set Tissue is available various places, but I ended up getting it from Amazon because its basic price (at the time, which was end of March 2021) was the least so long as I got enough other stuff to eliminate shipping costs. I have used the tape on three occasions since purchase, with satifactory results. Mostly used for weakened page edges, and in one case to cover a missing spot. The .78 inch width allows trimming down to something narrower and having spares piece(s) left for the next project/need. I might add that I also needed to buy an "iron" to apply the heat-set material. I have a son-in-law that is into remote control planes and copters, and he suggested checking out the hobby shops. We have a remote control hobby shop close that had a Hangar 9 Sealing Iron for like $16.99. I see them on the Internet for quite a bit more so be careful where you go. The Hangar 9 model had dialable heat control and a non-stick surface, and worked quite well.