This is a modification I made for my GoPro Hero3+ Black to make the GoPro sutable for underwater use on a pole or a tripod. I drilled a hole in GoPro housing where the HDMI connector is.  Glued a milled aluminium tube to the housing, and made ​​a plug with o-rings of the HDMI connector. Video out and power in. And now the GoPro is usable for underwater tripod or polecam recordings.