The Audio-Technica ATH-CKM99 In-ear Headphones minimizes unnecessary vibration with a hybrid metal case and dumper mechanism to achieve a really clear sound. Uses a stainless steel "acoustic register" in the earpiece for improved high frequencies. Coupled with the proprietary 14mm driver (the larges in ATH's canalphones) these earphones deliver rich sound across the audible range. It includes earbuds in 4 sizes (XS,S,M,L) so you can find the perfect fit. A great pair of earphones for audiophiles.