I figured these would be good because he can get them wet and just let them dry out quickly. 8kHz. Have not been able to test the noise cancellation feature. Ive saved quite a few pairs of shoes and made them last another couple of years. Theyve done fine. Ive had these for a week and a half and I genuinely dont know why I didnt buy these sooner. The heel was good height for her. I found I had to bend them and now I can wear socks with them finally. they were too big for me they are pretty much necklaces now Right price and good item for the $$.