Meet the KNEKT GP4 Trigger: a handy accessory that gives you one-handed control of your GoPro Camera’s functions. You will be able to start/stop video with one hand. The GP4 is balanced to match the weight of your camera. It has a spring trigger mechanism for instant shutter reaction with tactile feedback, so you can be sure when your camera has taken the shot.
The GP4 weighs 6.6 oz and has a a machined polymer handle with non-slip inserts and corrosion resistant military grade aluminum & stainless steel construction. It is designed to withstand outdoor conditions. Sets you back under $150.