Peace, mercy, and blessings of God be upon you. This piece is called a link. You buy it and have a tassel made for it by any jeweler. There is a picture for clarification showing how it looks when attached to the tasbih. You can use it to switch between different types of tassels and ownership beads if you have them. And also to remove the tassel when cleaning the tasbih so that it doesn't get wet. Sold wholesale and retail, and shipping is available.