If you need a power transformer for your 300B SE stereo build, this is a perfect solution. There are several options you can choose from to configure the transformer to your needs. It comes in both horizontal or facing down and vertical or upright configuration. You can choose 120V or 230V primary, and the secondary taps depending on the filaments you need. If you need even more custom option, please contact me. Note, that having a custom option not in the selection here will have an additional fee.