"Relay Camera Couplers from Tether Tools work in tandem with the Case Relay Camera Power System (CPS) to keep your camera powered continually with an external 5V USB battery pack or wall power. Relay provides peace of mind knowing you have an uninterrupted power source for your camera. Find the right one for your camera. Infinite Power for Your Camera With 11 different options to fit Canon, Nikon, Sony, Panasonic, Fuji and Olympus cameras, Tether Tools has the uninterruptable power solution for most popular cameras. When you're ready to get powered up, simply insert the Relay Camera Coupler directly into the camera battery port. Then attach the Relay Camera Coupler to the Case Relay CPS (sold separately) and power your camera with any standard 5V USB external battery (commonly known as a portable USB charger, which you can get most anywhere) or an AC power source, such as a wall outlet or generator. The Relay Camera Coupler combined with the Case Relay Camera Power System provides constant, uninterruptable power for your camera and is perfect for time-lapse photography, photo booths, video production and power-hungry LiveView shooting or any long day on the set. Need more power? Hot swap in another power bank and continue shooting while never losing power to your camera. Relay Coupler is simply an insert for your camera battery cavity that enables powering the camera via Case Relay Camera Power System. The coupler does not contain a battery or hold"