The standard, hard plastic, inserts in our inline leads are fine when using them on your main line, but when using any sort of leader you will need a Shockleader Sleeve. These softer inserts will still help to prevent tangles as well as gripping the swivel and allowing it to be pulled into the nose of the lead to create a bolt rig, but in the event that your line breaks, the lead will come free and can easily pass over your leader knot. Comes in a pack of 10.