The Tech 21 Sansamp RBI Rackmount Bass Tube Amp Emulator puts all of the preamp tone-shaping and fattening control of the popular SansAmp Bass Driver DI in a single rackspace and adds a host of new features: a dedicated mid control; individual level control for the XLR out to optimize your amp's output relative to the PA; effects loop; Mix 50/50 switch; 2 XLR outputs, one with level selection and a buffered unaffected XLR for running a dry signal to another channel. It also has 2 footswitch inputs: on/off and an output for chaining and toggling between 2 SansAmps.