I have used leader grips for many years, and some of them have cracked at the ends. But they are old! I bought some rope track light on Amazon
Amazon.com : Novelty Lights 3/8" Mini Rope Light Track, Mounting Rope Light, PVC Plastic, Clear, 4 Foot, 1 Pack : Tools & Home Improvement that work well, but don't have the rounded ends like the leader grips have. I have been thinking of replacing some of the leader grips and have not compared prices.