This is a super easy way to set a specific depth for your tip-ups or jigging rods.  This can be put on your line at any time and can be taken off just as easily.  Simply run your line over the center (between the 2 holes) section of the “S” and move the “S” up or down until you reach your desired amount of line hanging below the “S”.  Once desired depth is reached simply hoop your line over the top and bottom portions of the “S”.  I posted a photo with some clear fishing line and also a few others using baler twine so it's easier to see how the line should end up.  One of the photos with the baler twine shows just the top part looped over and the other one shows how it should look when both the top and bottom have been looped around.  If my instructions aren't clear enough please let me know and I will do my best to draw instructions and post them.