Precisely because they Don & APOs; t seal the ear completely against the outside world, they are quite useful: you can then wear the things even without a & quot; transparent & quot; mode, and yet you can & APOs; t completely lose contact with the acoustic environment. It's a security aspect right on the street. The ventilation of the ears is also better in the classic design of the earphones hanging in the earpiece and not sealing the ear canal. Not only does this prevent unhygienic contamination of the silicone attachments, but can also counteract painful inflammations in the auditory canal for people who suffer from severe wetting in sealed auditory passages. In this respect, a good choice: handset with current technology in both sealing and non-sealing design.