77mm Magnetic Variable ND8-ND128(3-7 Stop) Lens Filters - Nano-Xcel
SKU: KF01.1980
A
they have a back and a front thread so you can stack filters of the same size. Please note that stacking too many filters can cause vignetting. We therefore do not recommend stacking more than 2 filters together. I hope this helps you! Best regards.