The original Equation CBL3M-EPR 3 meter headphone cable for RP-15MC & EP. 3070 with 1/8" connectors. One end is push and twist to lock; the other end is threaded to optionally attach a quarter inch adapter (also available through Audio-Depot). 

This cable is lighter weight than what the other Equation headphones originally came with, but it will work for Equation RP20, RP21, XB1, and RP22 headphones as well as headphone by several other manufacturers. 

There is now also a CBL3MC-EPR Coiled version of this cable.