The Radial ProDI is a high-quality, full-range passive direct box equipped with custom made audio transformers for exceptional signal handling without saturation and with extremely low phase distortion in the critical bass and mid regions. The result is exceptional clarity and definition at an attractive price point. Ultra-compact and made of 14 gauge steel, both ProDI models feature internal I-beam construction with a 'book-end' outer shell for extreme durability in the most demanding environments.