The Zoom H4 is a handheld solid-state recorder with built-in stereo mic, two combi XLR/quarter-inch jack inputs and USB output. The entire unit measures 70 x 152.7 x 35mm, and looks rather like a device you'd use to stun the Invaders From Mars.
Once the box arrived, I took a quick spin through the manual and fired up the recorder. It runs on just two AA batteries, though you have the option of 9V DC power from the supplied transformer, and records onto SD cards. A 128MB card is supplied, but you can now get 2GB cards fairly cheaply. Two batteries will give you about four hours' recording time, so a cheap 'Dirty Dozen' will give you a full 24 hours' recording. However, there's no meter to show you how much power remains, which is a pity. Two cardioid mics, in a sort of X-Y configuration, are located at the top, protected by a little cage-like structure, on top of which sits the supplied foam windshield: a welcome addition that you will definitely need outdoors. The two jack/XLR inputs at the bottom can serve either as mic inputs with phantom power, as line inputs, or as high-impedance inputs for connecting electric guitars and the like.