I used a gopro 4 black before and have an Inon UWL-G140 for it. Just updated the age old camera with a gopro 13 I wonder what's the best option to fit the lens on the original gopro dive housing? Compatibility with my polarpro filters (basically gopro's stock diving & snorkeling orange/red filers) would be a fantastic plus.

Apparently I got two options: stock Inon SD front mask (haven't found a UK dealer yet): doesn't seem to be polarpro compatible nor has its on provisions for filter.

The Backscatter mount, here it says is compatible with Inon SD lenses (should be verified though). Maybe it doesn't work with the polarpro filters but at least I can buy the backscatter filter inserts.

I hope you can make that work. I haven’t looked into it in a while, but it seemed easiest to go for the Backscatter Flip filters, though there are likely better solutions out there.