I personally did not size up because I have a narrow foot and if they stretch, it will be too big. Its quite odd that a shoe sized for US 4 to 5 would still be a bit loose on a size 6. I highly encourage people to plan the setup first, because it is not remade at the spot. fit is true, durable and very comfortable. A green light means fully charged. They are perfect! Wow, these are so worth the money. My toe could be bandaged and still fit, with room to spare! No problems with the mount it holds my phone well and withstands any knocks or jumps. Awesome rugged boom box.