This is a 25 key USB MIDI keyboard, designed specifically with iOS (iPad, iPhone) devices in mind, that also works with Mac and PCs. The keys are full-sized and velocity-sensitive, making it perfect for getting more out of programs like Garageband, and unlocking the various synths and drum machines contained within. The pitch, mod, volume and pan knobs allow you to control the signal going into the computer, and the keyboard is powered through the USB cable only, keeping you free of cables and power adapters. Inputs for sustain and expression pedals also give you added flexibility, and it’s highly portable. It also comes in a larger 49 key version.