Adopt a "spiral dot" in the earpiece inner wall. Compatible models: HA-FX1100, HA-FX850, HA-FX750, HA-FX700, HA-FX650, HP-FX500, HA-FXT200, HA-FXT200LTD, HA-FXT100. at the receiving country side. Due to accidental circumstance it may exceed standard period.
eBay