Four conductors: 15 foot (450cm) extension cable terminated with a 1/4 inch (6.3mm) plug and a 1/4 inch (6.3mm) jack.

Twelve conductors: 12-foot extension cable terminated with a 1/4 inch (6.3mm) plug and a 1/4 inch (6.3mm) jack.

The cables are constructed from the same high quality super annealed copper wire as the X-Series headphone cables, with braided sheathing. For longer lengths cables may be piggybacked up to 3 cables. Grado guarantees no degradation of sonic quality with Grado headphones while using their extension cable.