Originally Posted by ponyriver
The name of the clear plastic film is 'InvisiGRIP' by Omnigrid. Here's an easy way to cut it. Using the ruler that you want to attach the film to: place the film (which is covered with a white stiff paper) with the film down and the paper up. Now, place the 1/4" marks on your ruler both horizontally and vertically along a 90 degree edge. (you can also achieve this by cutting exactly around the ruler and then removing 1/4" from just one side and one end of the cut piece.) Keep the cut piece with the film down & the paper up, carefully remove the paper. Lastly, carefully place the ruler on the plastic, centering 1/8" on all sides.
(note: the side of the film that was next to the paper is the side that sticks to the ruler) Hope this is helpful.
Thanks for the info, Ponyriver...and to everyone else who has given such great ideas! I have one of the bath grips that I will be using when I get to cutting more strips/pieces. (The darned thing never would stay on the bathroom wall! It will be put to better use on my quilting rulers!)