Theres also a TPU cover if you dont want to use the paddle button. My foot was too tall / too big around to slide in all the way. Exchanged for the next size up, a 7/8 and it fits great. 391684] Under-voltage detected! Only fits 6 pairs of shoes unless you have tiny feet, then maybe you could manage 8. I complained and got a replacement that month. I will give two more stars for the effort there and will give them credit for a defect explaining my troubles. Im very dissapointed with both the shoe and response I received. they take a short time to break in but when they do they are so comfy. Tested on other devices, same result.