Check the listing for details. Grace Design REX Microphone Preamp Pedal with Boost. Condition: Very Good - Refurbished. Listed at 553.50 USD. Grace Your Pedalboard with a Preamp Like No Other The innovative Grace Design REX Microphone Preamp pedal equips artists with instant tone-shaping tools for enhancing the definition, volume, and EQ of any mic! The REX facilitates all the transparent clarity and openness of traditional Grace Design preamps, but it’s optimized for quick single-user operation. With the REX’s user-friendly features, you can shape vocals, add a dynamic boost, amplify acoustic instruments, and even monitor levels. Whether you’re an avid preamp user or a curious outsider, pros at Sweetwater can personally speak to Grace Design’s unparalleled craftsmanship and distinct preamp quality. The REX echoes the company’s legacy at a size that fits into guitar cases, backpacks, or pedalboards.