Protective UV Filter
This filter is intended to be installed semi-permanently in place of the lens cap, to protect the lens from incidental scratches and finger prints. While the durable scratch resistant UV coated polycarbonate material will protect your lens, like any filter placed in front of your primary lens, it can produce unwanted flare and image artifacts in certain light conditions. It also may be subject to some degree of fogging in certain circumstances. While this filter is intended primarily as additional protection for your Gopro lens, it does not render the housing waterproof or even water resistant.
While some photographers insist on a filter to protect their camera lens, others prefer to have nothing at all in front of their lenses, which might, if even slightly, degrade the performance of their optical system. Either option is yours. Use the lens cap which comes with your Apro camera housing or add this optional filter for additional protection while filming.