Chafing springs are a very useful item, they help prevent line damage when your leader or other line comes in contact with metal. It reduces the chance of a break-off, simplifies rigging, and is a basic necessity when rigging up trolling lures or fishing heavier lines with bait for larger grade fish. If you are rigging up some lures, you need 'em. And, if you are heading out on a long range trip targeting the BIG TUNA, you'll absolutely need some for use securing your hooks to your line/leader. A crimp connection will prove far less bulky and restrictive than use of the typical heavy San Diego knot for rigging a hook bait. They have become a basic long range rigging necessity. Over the past several years they've become more and more hard to find. Sevenstrand used to offer 'em, then when they were purchased by Pure Fishing the product disappeared. That left us with the old, bulky, plastic type springs which were a bit of overkill in terms of size and not as nice to work with. Our springs are made from stainless steel, for long term durability. Frankly, I will use these over and over, have some in my long range bag that I've used for years now. Size #1: 1.2mm for 80-130# line Size #2: 1.4mm for 150-200# line Size #3: 1.6mm for 200-250# line Size #4: 1.8mm for 250-300# line Size #5: 2.0mm for 300-400# line