Fostex T40RP Closed Ear Stereo Headphones Item #: FOS T40RP 

Fostex T40RP Headphones are excellent quality headsets with Regulated Phase, a new transducer technology which offers the finest quality audio reproduction. They're esed by professionals on stage & in studios the world over.
The T40RP utilizes a newly designed development called an RP Diaphragm. This unique Fostex technology employs a copper foil etched polyimide film to provide resistance to high level input peaks of up to 3000mW combined with a neodynium magnet for high sensitivity and excellent transient handling.

Fostex's RP headphones employ Regulated Phase transducer technology (for which Fostex has earned over 40 international patents) for exceptional performance.