The APH-4nPro bundles the most useful accessories for the H4n Pro into one package. You get the AD-14 AC adapter for long recording sessions without worrying about battery life, a USB cable for computer connectivity, a hairy windscreen for outdoor recording, a splitter cable so two people can monitor on headphones simultaneously, and an attenuator cable for connecting the H4n Pro's line output to a DSLR mic input.

That attenuator cable alone is worth noting, since plugging a line-level output directly into a camera mic input without one will clip badly. A practical, well-thought-out kit for H4n Pro owners who shoot video or record in the field.