The LensCoatExtender set includes a cover for the Canon 1.4 and 2.x 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."
Please NOTE: This set is for the old (original) set of extenders. If you have the new Extender Set III then you need to order this: LensCoat Canon Extender Set III