Product Details 【Manufacturer】 SONY 【Model】 SONY MDR-E252 The "MDR-252," the first model of "N・U・D・E," was Sony's first inner-ear headphones, completed with a zero-fit concept that makes you feel like you're not wearing them. It uses a 16mm driver unit. In fact, it can be said that the product was conceived from the 16mm size of the driver unit. Simple cleaning has been done. Sound output has been confirmed. Made in Japan. Please understand that this is a used item, and purchase accordingly. Thank you.