LED-based Voltage Monitor
The EMW CV Monitor is a simple and useful module that can used to measure the voltage of an incoming signal. The module displays voltages ranging from +/- 5v using LEDs for every 0.5 v increment.
http://www.electronicmusicworks.com/detalhes.asp?id=91&produto=120&loja=EURORACK
No info about availability.
$89