Advantages of toroidal transformers  High Efficiency  Smaller in size  Lower in weight  Less mechanical hum  Low exterior magnetic field  Low off load losses  Single mounting point Technical Data Capacity: 20VA-25000VA Phase: Single Input: AC Power with Voltages of Various Countries Output: AC Current, Voltage, According to Customers Requirements Frequency: 50-60Hz Voltage Regulation: 12%-3% Manufacture Standard: GB/T15290-94, GB/19212-2006, GB2828-2829- Insulation Class: B, 130 Celsius Degree; E, 120 Celsius Degree 87 Temperature-rise: ≤85 Celsius Degree Winding conductor material; usual us copper, can use aluminum if you have special requirements