The 300VA toroidal audio power transformers have static shield between primary and secondary coils to improve the isolation and noise interference. They are specially designed to work on all standard 115V or 230V at 50Hz or 60Hz. These transformers have heavier gauge wires than the normal requirement to avoid the copper lost during the full power output. And they also have the magnetic shield around the outside to reduce the magnetic leakage. The dielectric test is more than 3500V in between primary and secondary coils. In most of the cases, this transformer can be output 20% more power from its rating at 60Hz power source without any problem. This transformer comes with 1 rubber pads and all mounting hardware.