GoPro Session Filter Clamp / Holder / Mate Box

thingiverse

To attach a filter of your preference in front of the GoPro Session lens, all you need is an easy-to-use mount. I personally favor using a little cutout from an ND Roll like this one: https://www.thomann.de/intl/sk/lee_filter_roll_211_09neutrdens.htm. However, you can use anything that can be cut to size, such as color filters or other materials.