密閉型ヘッドホン
Meanings
1
closed-back headphones
Headphones with sealed earcups that block outside noise and prevent sound leakage. Often contrasted with 開放型ヘッドホン (open-back headphones).
See also: 開放型ヘッドホン
Closed-back headphones have little sound leakage, so they are easy to use even on the train.