via
this auction

"Be minded that this unit does not produce any sounds.
The idea is such:
1. Get some trigger pads or anything that produces an audio click.
2. The unit turns trigger input into a velocity responsive MIDI note!
This is almost too cool to be true.
Get a series of metronomes together and create weird and random sequences.
Plug your old-school drum triggers into it!
Get creative!
Assign any channel to produce any MIDI note!
Create four different programs to the unit's memory.
Stay creative!"
Update via scotty in the comments:
"when used with the casio rz-1 (as a trigger) you can have total control over
the sequences, since the rz-1 has separate outputs for each drum. this means you
only have to plug one thing into the dz-1 to get a ton of cool sequences. not to
mention it looks like it could be the rz-1's baby brother "