Eagle Claw Level Line Leader Links are easy to use line-to-leader connectors. This size handles the popular size level lines. These Leader Links are smaller in diameter than most splices, loops and nail knots, and they add simplicity and speed to changing lines.
Eagle Claw Level Line Leader Links are constructed of smooth, strong, lightweight plastic.
These come in packs of 5 leader links.
It's not what they're designed to do although there are teeny-tiny instructions for using them as bobber stoppers printed on the packaging - magnifying glass not included. Ran into someone using them as bobber-stops and thought I'd try it.
I'd give it mixed grades on the results, but I'm sure it's my lack of experience. Sometimes they didn't "lock" in position, but they can always be removed and re-positioned on the line, so you're not stuck with cutting the line to change the position of the bobber.
Have not tried them as leaders-links, the task for which they are made.