I use the Knit Picks Harmony circular needles and the Zephyrs tips. Shortly after I had bought the Try it set, I was using the Zephyr tips on the cable and one of the needle tips broke off. It was just the very tip that broke and left a flat spot. I emailed Knit Picks about it and they sent a replacement set of the Zephyr tips in the size I had , no questions asked. Any time I need another set of needles or circular needle, I will buy from Knit Picks. Love the service, that is very rare now days.