Sometimes we get things that don't seem to exist... like this. I didn't even know ESP ever made pedals, let alone bass-specific stuff. It's old enough to not come with a 9v input, so it's got to be powered by a battery. It's good on bass, the two band EQ is pretty powerful and it adds some punch and presence into the mix. It's also awesome as a clean boost pedal for guitar, it sounds terrific into a slightly dirty amp. ESP tend to do everything well, and this is no exception. 

Model: ESP Bass Pre-Amp
Made: Japan, 1990s approx
Type: boost-preamp
Power: 9V battery, not included
Switching: buffered bypass
Equivalent new street price (approx): n/a
Mods: none
Accessories: no box or manual
Condition notes: used, few little marks, fully functional. Overall: very good condition