E-MUs Tracker Pre USB (Universal Serial Bus) 2.0 Audio Interface/ Mobile Preamp is the ultimate portable USB (Universal Serial Bus) audio interface for Mac & PC offering pristine 24-bit/192k Hz recording & playback direct monitoring & a host of professional features in a compact USB (Universal Serial Bus) bus-powered package. The Tracker Pre USB (Universal Serial Bus) provides users with two Class-A ultra-low noise Mic/ Line/ Hi-Z preamplifiers that can be run independently or in stereo to record guitars keyboards or microphones with optimal audio performance.