The 2558A is a low-cost, high-precision instrument capable of outputting a wide range of AC voltages and currents for the calibration of electric meters and other devices. In terms of accuracy and other performance characteristics, this new model is a significant upgrade from our previous model, the 2558 AC voltage current standard, which was introduced in 1979 and discontinued in 2003. Providing output ranges of 1.00 mV to 1200.0 Volts AC, and 1.00 mA to 60.00 Amps AC makes the 2558A the product of choice for the cost effective calibration of AC analog meters and other AC measuring instruments. Front panel controls and various computer interfaces enable the 2558A to be intuitively operated manually or controlled by an ATE system.