The Zoom APH-4nPro Accessory Pack is specifically designed to add more usability to the H4n Pro Handy Recorder with better connectivity to DSLR cameras. The accessory pack include an AC adapter to always be powered up during long recording sessions, a windscreen to effectively reduce win noise, a USB cable that allows you to connect to MAC and Pc to transfer your audio files over, a splitter cable that allows you to monitor with two headphones and a attenuating cable that lets you connect the line output of the h4n Pro to the microphone input of a DSLR camera.