Cans is recording studio slang for headphones. In the recording community, as it is in all fields that use equipment with long technical names, certain commonly used items find their names shortened for convenience sake, or coolness factor.
Headphones, which are mainly used for monitoring during recording, became shortened to phones, and later to "cans", which is a reference to the old trick of running a string through two cans (like coffee cans) to make a crude telephone. Recording studios are famous for technical jargon turned slang.
"Cans" is in the HS Code "7310.21"
- -- Cans which are to be closed by soldering or crimping
"Cans" is in the UNSPSC Code "24112200"
Cans and pails