This item is a vintage Xedit Model-20P professional audio test unit. Designed by the legend himself, Dan Dugan, in San Francisco! The device powers on but I have no idea how to use it and I don’t have any tape equipment anyway so wouldn’t be able to test it properly. Function: It is designed to measure audio speed accuracy, specifically for checking drift and flutter in tape machines and recording equipment. Interface: Features a prominent analog needle gauge for precise visual monitoring of audio fluctuations and various calibration buttons. Usage: These devices were commonly used in broadcasting and recording studios during the 1970s and 1980s to maintain high audio quality standards.