Primark. Not sure what they call them, they have others that I got that were a disaster and never stayed on properly but these ones are like a mesh material and very very stretchy - as in you'd think there's no way they'd ever fit on your feet. I think they might be "sports" on the label. They come in a three pair pack. They are super, really comfy, stay on all day and are really low so don't show under your trainers & converse.