The DS Flip Up Red Filter is ideal for improving your underwater photos and videos. When you take your action cam below 5m underwater then the colours begin to fade and red if the first colour to go. By simply attaching this Flip Up Filter you can choose to flip the filter up when between 1 and 5 meters and once you go below 5 you simply flip it down to improve your images drastically. Its really easy to use and makes an incredible difference. This is a highly recommended GoPro accessory.