I review the article here about 1 year after purchase. The range for optimum voice quality is only about 1 meter. In order to have zero faults I recommend the mobile phone in your shirt pocket or bra stuck. After about 9 months the pinna has given up the ghost, and thus was wearing uncomfortable. Well a year now has now completely ceased operations and can not be switched. Actually, I'm quite happy now soon to use another. :-( PS: The design is super.