Editor Reviews:

Product Description:
Grado offers a 15 foot 450cm extension cable terminated with a 1/4 inch 6.3mm plug and a 1/4 inch 6.3mm jack. This cable is constructed from the same high quality wire as their headphone cable. For longer lengths the cable may be piggybacked up to 3 cables. Grado guarantees no degradation of sonic quality with Grado headphones while using their extension cable.

Rating : - Safe to buy!
I use these with my RS-1. I'm a very picky listener. These do not change/degrade the sound whatsoever.