The Kiwi Ears Étude was developed to showcase the KVT - Kiwi Vibration Transducer. Our in-house vibration transducer is not like bone conduction drivers currently used in earphones. Rather, it is more akin to scaled down miniature vibration drivers that are used in bluetooth vibration speakers. The KVT uses strong N52 neodymium magnets that are suspended by heavy-tension spring systems that physically vibrate a conduction plate upon actuation by electrical currents. The KVT provides physical tactile vibrations to relay the sound, enhancing low-mid acoustics. DUNU S&S Eartip is availble in 4 options according to the eartip size: S/M/L, S, M, L, which can meet most people's needs. The main difference of different size lies in the outer diameter of them, from 8.98-11.5mm. And each option comes in 3 pairs in total.