Probably the mist iconic octave pedal of all time. This is an early example, dating to December 1984 and made in Japan. The thing that makes these good is the all-analog circuitry, which doles out thick, smooth, fast-tracked beefiness with glorious abandon. It took me all of five seconds to be smiling ear-to-ear.

Model: Boss OC-2 Octave 
Made in: Japan, Dec 1984 (serial 494600)
Type: octave
Power: 12v AC supply or 9v battery (not included)
Equivalent new street price (approx): n/a
Mods: none
Accessories: no box or manual
Condition notes: used, few minor marks, fully functional. Overall: very good condition