StickTite 20/20 Stick-on-Bifocals. Any Solar Bat sunglass style in any of the sunglass lines can be converted to bifocal with the easy install Stick-On-Bifocal. These stick-on-bifocals are easily cut to size and are applied to the back surface of the lens using only warm water. They are available in powers of +1.50,+2.00 and +2.50.