This is a 37mm-threaded CPL Filter from Neewer for the Vantrue E1, E2, E3, E1 Lite, and N4 Pro dash cams. It's made with multicoated HD optical glass and an aluminum frame. The filter reduces glare and reflections from nonmetallic surfaces such as windows or bodies of water. Screw the filter onto the dash cam lens, and then rotate the filter ring to achieve the desired effect.