PRESTON's Slip Dacron Connectors are available in four sizes to accommodate all sizes of elastic, from our thinnest solid elastic to our thickest 19 Hollo elastic. The beads are fine and soft with an internal recess in which the knot can be placed in the elastic. To attach it, tie the elastic around the dacron loop, then slide the bead over the knot. This acts as a buffer and also protects the knot. The Dacron cord is color coded: Micro - Blue, Small - Red, Medium - Green, Large - Orange.