They come in red, black and yellow and work good on mono. Not so good on braid. The braid wears them out sliding them up and down. To keep the knots tied tight make sure when you first put the stop on that you pull it as tight as you can and leave some string (about 1/4 inch) on the tag ends and if it gets loose again take a two pairs of pliers or your nails and tighten again. They come loose from moving them around a lot.