Cable temple covers are soft and flexible. They are easy to install on vintage eyeglasses with straight or C-shaped, curved wrap-around bare-metal temples. They are more comfortable than plain metal cable temples that wrap around your ears and rub them raw.
Carefully measure the diameter of your eyeglass temple with a micrometer or caliper to determine the correct temple tip size that you need. A ruler is not accurate enough. The thickness of the lines on a ruler, scale or tape measure is often greater than the difference of the sizes offered.
Apply a little silicone adhesive to the bare cable temple end before installing to keep the temple covers in place. A little dab will do ya.
Cable temple covers are made to size. They will not shrink like heat shrink tubing.