These headphones are specially designed for long-time wearers.

wearers 是名词 wearer 的复数形式。wearer 由动词 wear（穿戴、佩戴）加上后缀 -er（表示"做某事的人"）构成，指"佩戴者、穿戴者"。wearers 在这里特指"长时间佩戴耳机的人"。