Radial ProDI, Passive DI Box, Radial Item R800 1100. The ProDI is a passive direct box designed for use on stage or in home recording studios, with the ability to handle high output instruments without distortion, and a transformer-isolated output to eliminate noise from ground loops. It features a custom-made transformer with exceptionally linear frequency response from 20Hz to 18kHz that is able to handle high levels without saturation, making it ideal for electronic musical instruments and audio equipment. ??Compact passive direct box for stage and studio ??Able to handle huge transients without distortion ??Transformer isolation eliminates noisy ground loops ??-15dB PAD switch for level reduction from high output devices ??Ground lift switch eliminates ground loop hum