These Grado SR60 on-ear headphones have been a popular open back model for decades, and deservedly so.  They have a well balanced low distortion sound are easy to drive to high listening levels with a phone, computer, or tablet, due to their low 38 ohm impedance.  A sturdy cord with a 3.5mm plug is ready for most portable devices, and a gold plated adapter is included to convert to a 1/4 inch plug.  The foam earpads have been replaced and are readily available at reasonable cost for future replacement if needed.  These have had little use and are in mint condition.