This is the ATH-A100Ti, a monitor headphone with a titanium housing that Audio-Technica released in 2001 as a limited edition of 2,000 units to commemorate its 40th anniversary. I purchased it new at the time of its release. Although it's a rare limited edition model, currently, sound is not coming from one side (right side). A specialist shop has diagnosed a driver failure. The ear pads have been replaced with generic ones. There is no box or instruction manual. There are scratches and minor imperfections commensurate with its age. Please understand that this is a junk item before purchasing. Immediate purchase is welcome. Price negotiations are not accepted.