Tried with 2, 900mAh rechargeable batteries, powering with 2. I looked at several and after comparing features, size, price and ratings. They are very warm and my feet have never gotten cold while I was wearing them (and that is the sole reason I purchased them). Sparkle and simple My last pair of Teva had a rubber foot bed that made your feet sweat. I like that bec other cases it will protect the top, but you have to actively put the top back in place when you open and close it. The slide-in with velcro strap is not a stable design. ME QUEDARON PERFECTOS, MUY COMODOS, LO UNICO MALO ES QUE EN UNO, SE ESTA ABRIENDO UN POCO DE UNA COSTURA DEL FRENTE. Oh and I guess i am not crazy about the fact that u would have to take it off and on over ur head each time u wear it. Ich habe mir den gekauft, um meinen AKG 3003i zu ersetzen, jedoch diesen behalten und den Xelento zurückgeschickt.