Midilooper, the latest hardware control tool from Czech brand Bastl, is fairly self explanatory, functioning much like a traditional looper pedal but working with MIDI rather than audio.
The unit has three independent voices, each of which can be assigned its own MIDI channel, allowing it to send looped messages to up to three instruments at the same time. The workflow appears fairly simple - simply feed the device a MIDI input, hit record, and instantly create a loop of note, CC data or both.