If you are shooting underwater video a flat lens is a must, otherwise you will get the fishbowl effect when you playback your video. You can pick up an inexpensive polycarbonate lens at http://freedivingspearfishinggear.com/61-flat-underwater-plastic-lens-gopro.html they also sell the lens cap here not to mention several types of gopro HD cameras and accessories. This install works for the gopro hero camera housing, I also included the suggested settings for best underwater movies.