With this thin yet solid tube, I noticed I can make the neatest nail-knot ever.
This is the end result (I didn't clip the excess for the picture).
I actually can make a nail-knot without this tool. And it does have accuracy and strength. But this nail-knot with the splice needle goes through the guides much easier whether rigging up or fighting big trout that have to be dealt with just around butt-section.
I hope some of you out there like this tool and nail-knot.