Fostex EX-EP-91 are OEM replacement ear pads made exclusively for the TH900mk2 — Fostex's closed-back flagship dynamic headphone featuring the Biodyna bio-cellulose diaphragm and a neodymium magnetic circuit with 1.5 tesla flux density. The pads use low-rebound foam wrapped in protein leather derived from eggshell membrane, matching the factory material specification exactly. This is the only model in the Fostex EX-EP accessory line that uses this specific outer material, which sets it apart from the leatherette-covered pads used across the rest of the RP and TH range.
Why the outer material matters on a closed-back flagship
Protein leather from eggshell membrane has a noticeably softer, more pliable surface than standard PU synthetic leather, and it breathes better — reducing heat build-up at the ear during extended listening. For a closed-back headphone used in long critical listening or mastering sessions, that thermal management directly affects comfort over time. More critically, the low-rebound foam beneath is matched to the TH900mk2 cup profile: it maintains consistent contact pressure around the full perimeter of the ear, preserving the acoustic seal of the closed chamber. When that seal degrades through pad wear, bass extension drops and the stereo image loses definition. EX-EP-91 restores both.Compatibility and installation
EX-EP-91 are exclusive to the TH900mk2 and are not interchangeable with the original TH900 or any other TH-series model. The mounting system uses a stretch-and-clip design: pull the old pad away from the cup housing, stretch the new pad's rear flap over the cup rim and press into place — no tools required, around thirty seconds per side. No disassembly of the headphone is needed.KEY FEATURES
- OEM Fostex replacement — exclusive fit for TH900mk2
- Protein leather from eggshell membrane — softer feel and better breathability than standard PU leatherette
- Low-rebound foam core — even lateral pressure distribution, reduced fatigue
- Restores factory acoustic seal of the closed chamber
- Tool-free installation — stretch-and-clip mounting onto the cup rim
- Sold as a matched pair
TECHNICAL SPECIFICATIONS
- Model: EX-EP-91
- Outer material: Protein leather from eggshell membrane (black)
- Cushion type: Low-rebound foam
- Color: Black
- Compatible models: TH900mk2
- Package contents: 2 ear pads (one pair)
- UPC: 636827307246


