The phot r 37mm adapter ring for the gopro hero cameras allows you fit a 37mm filter and a 37mm lens cap to your gopro camera this means you can use a variety of filters on your gopro such as uv circular polarising neutral density and coloured filters and any other 37mm diameter filters that you wish to use by adding filters to your gopro it will help to enhance the quality of your photos and videos without using any editing software this listing is for the adapter only allows you to