The Schatten EP-01JG is a small, lightweight piezo sensor that is meant for one time installation on an instrument's soundboard. The pickup comes with 18" of shielded cable and a standard 1/4" TRS (tip/ring/sleeve) endpin jack with a gold strap button instead of the standard chrome strap button.
Since this unit is meant primarily for protected interior installations, the piezo element is not 'potted', but is instead covered with an acoustic foam pad. Due to the nature of the piezo and the fact that it is not a 'potted' unit, this pickup has great output and full response. No preamp is required.
The EP-01 is a sensible choice for use in smaller and less expensive installations or for experimentation purposes. Feedback rejection for this pickup will depend upon how it is installed and exactly where it is installed. This is a general purpose pickup and is not suggested for stage use. Soldering required.