IWISTAO Tube Amp Power transformer 300W 350V-0-350V 5V 6.3V 3.15V-0-3.15V Silicon Steel Sheets Oxygen-free Copper Wire Audio DIY.Model No: WHFT-PT300W, It is made of silicon steel sheets, pure oxygen-free copper wire carefully. Painted with special thermal black paint, look quite luxurious, it is a better choice for making tube amplifier.