This case matches with GoPro Hero 5-6-7.
I designed those cases with 20 and 30 degrees. This case allows you to fix your GoPro on your SX218 Petit Soldat WITH ND Filter.
You will find a support to be able to fix other HD cams on your SX.
Please print it in TPU (otherwise you will not be able to fix your GoPro in).
So have fun !