Earpieces are an important factor that ultimately determines the sound quality of earphones. The "Sedna Earfit" series has a design and shaft structure based on data obtained by analyzing the ear canal of 788 people, which enables a high level of fitting and fixing force to the earphone nozzle, and at the same time improves sound insulation. A high-grade replacement earpiece that ensures straight sound travel with a unique shape and improves the high-frequency characteristics along with natural sound output. "SednaEarfit™ XELASTEC" aims to achieve a high level of sound quality and fit in the SednaEarfit series, while maintaining sound quality and further improving the fit. Was developed by "XELASTEC" is a combination of X (NEXT) + ELAS (ELASTOMER) + TEC (TECH), a compound word consisting of X, which means the next generation, ELAS, which means thermoplastic elastomer, and TEC, which means high-tech.