It?s quite large for a closed back design and probably the largest and most well-constructed that I have heard in its class. Wireless charger also worked with my Samsung phone as well. I was a little shocked. After having another pair of slippers last less then a year, I found these. To remedy this, you can use a USB cable keeping it powered all the time. The Viper is very comfortable and lightweight and the actual left and right buttons felt very positive to click and Im sure they would last for a long time. In short, it is impossible to put this thing together with out drilling out all new holes. The light at the bottom of the charging base tells me that all is okay when I place my phone on the charger, then goes out a minute or so later. Perfect flip flops. I wear it on days where I dont feel like wearing a traditional bra.