It's a chainsaw in a box. It has four knobs you can dime. Once the knobs are dimed, you can get about your regular day job of ritual sacrifice, actual murder etc. Good for playing Swedish music that isn't Abba or Millencolin.

Model: Boss Heavy Metal HM-2
Made: Taiwan, 1988-91 (serial sticker too warn to read)
Type: distortion
Power: Boss ACA 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: good condition