Valcom V-9984-W Remote Input Module Provides 1 Balanced XLR Microphone Input  1 Auxiliary Input for MP3 Players, CD, DVD or PC's Connects to Main Control Module, w/2 Pair 24 AWG Cable Screw Terminals for Easy Connections Volume Control for...

Valcom V-9983-W 2-Channel Mixer - Expandable to 10 Channels Built-In Compressor (Option Switch Controlled) for Automatic Consistent Volume Level Adjustment Even When Voices Vary - Low to High  Master Volume Control for Optimum Volume Adjustments...