I needed a replacement MMIC for a piece of equipment that had failed. There were no markings on the original, nor any schematics available, but a little 'reverse engineering' soon determined that the actual device was probably the ERA-6SM. It was promptly dispatched, and when I placed it in the circuit, voila, everything worked perfectly, the device operating voltage, in-circuit gain and frequency response was exactly in accordance with the manufacturer's specifications. What more can I say? A perfect replacement.