This 4-channel control pedal is designed for the Microtubes 900 bass amp head. It provides easy access to the amp's options: the Clean channel for a clear, biting, transparent, and incredibly versatile sound with 4-band EQ; the VMT (Vintage Microtubes) channel to boost the mids and achieve the warmer, more neutral sound of the Vintage Microtubes; the B3K channel for the aggressive and punchy sound of the Microtubes B3K; and finally Mute to cut the amp output for tuning, for example.