I, too, purchased a BTZS focusing hood for my TK 45. I do not recommend the product for two reasons

First, it takes more time to place this on the camera than it does to put on a regular dark cloth. If your camera design allows the hood to be left in place, this would be less of an issue. My TK 45 does not, because it is not possible to put a film holder in the camera with the hood in place without damaging the bellows.

However, the main reason that I dislike the BTZS is because it is constructed of waterproof nylon. I tend to be warm after hiking with my camera. Placing my head into a waterproof cloth tube has predictable effects: the ground glass and my glasses are quickly covered with condensation. In the winter, this turns to ice. I asked about returning this hood, they didn't seem interested.

If you decide to purchase a standard focusing cloth, make sure it is made from a material that breaths.

Bruce