The Quick Snap makes it easier to change the lure during ice fishing. One end of the Quick Snap is tied to the line and the other end is twisted into place in a second. The design of the Quick Snap holds the lure well, even if the fish is pulling hard at the end of the line. Quick Snaps are commonly used in lure fishing and ice fishing. You can tie the Quick Snap on monofilament line with a normal lure knot, but on fiber line you must use a non-slip knot. Quick Snap sizes by fish species: XXS and XS Perch/Whitefish S and MS Perch/Grey/Pike/Salmon/Trout M Pike/Pike/Made/Sea trout L and XL Pike/Sea salmon You can find the strengths in the product information.