almost all of us have the similar trouble for finding only a piece of socks rather than a pair.(這里稍微異議一下） it will be a more difficult for the blind to find a pair of socks.thus,this button is especially design for them.it was stitch on each sock,with the braille for distinguishment.the button enable te user to match and integrate two pieces of socks.this device enable the blind to avoid embarrassment of misdressing and the loss of a piece of sock