For SAle: (2) 77mm Aluminum Filter Stacking Caps. Used. but in very good condition. I used them a bit to protect the fronts of my filters/lenses, both while mounted on my camera and unmounted. (Male and female sides, allows for "stacking of 77mm filters together, and then protecting the exposed side of either/both ends). Sells new at B&H for $16.95; selling for $12 ea, shipped conusa.