The speaker and the sim card slot is horrible. No Mic, so of course it doesnt work. These two strap sandals are cute and I had no issues with comfort. Though connecting to two devices is not claimed in the manual, most BT headphones today do support it, so thats the second star off. I am going to order a few more pairs of these because I like them so much! This is a very nicely designed and built headphone. Despite this they don?t slip off your feet because of the way the inner sole is designed. Spero con questa mia opinione di esservi stata utile. They are so comfortable, good fit (size 5 and D width fitting, but not narrow feet). Bars are mad of steel which make them strong.