TM500 Liquid Crystal Driver
The (Unknown mfg) Liquid Crystal Driver is a plug-in for the TM500 system.
Mentioned in Dennis Tillman's List of TM500 and TM5000 equipment. An example turned up on eBay in October 2019 in a lot with two 5000-series oscilloscope vertical amp plugins. Only low res photos provided. Listed as TM500 plugin but compatibility unknown.