LensCoat lens covers offers your valuable equipment some protection from scrapes and bumps, preserving its resale value. They also help break up the shape of your lens, making it less noticeable to wildlife. The LensCoatExtender set includes a cover for the Canon 1.4 III and 2.x III extenders. Two small holes line up with the red dot indicator, making it easy to quickly line up your extender with camera mount and lens with the cover installed as well as a hole for the extender release.