The octave pedal with moooore. One octave up, two down, plus a clever option to just double the lowest note you're playing. Add some chonk to your honk.

Model: Boss OC-5 Octave 
Made in: Malaysia, Oct 2021 (serial A1N8778)
Type: octave
Power: standard 9v negative supply or 9v battery (not included)
Equivalent new street price (approx): $249aud
Mods: none
Accessories: no box or manual
Condition notes: used, few minor marks, fully functional. Overall: very good condition