FiR Audio IEMs feature bass that goes beyond simply being heard. The IEM entire chassis is uniquely coupled to act as a secondary transducer so you get to physically feel the bass as if you were listening to wedges. FiR’s ATOM (Air Transferring Open Module) is a pressure release system that widens the soundstage & also assists in alleviating ear fatigue. The FiR direct treble system removes the spout from a balanced armature driver, allowing a widening of the air pumped from it.  Their M5 even has a tubeless electrostatic tweeter! Their 3-year warranty even includes the cables! FiR Audio manufacturers the first tour designed, from the ground up, IEM vacuum to clear out the dirt, dust, & wax buildup that gets lodged deep inside the small tubing & bores of your in-ears, an IEM Cable Tester, IEM Dryer Moisture Extractor,  & more.