Wintergreen Lighting All-in-One Christmas Light Clips for C9, C7, Icicle Lights, Mini Lights on Gutters, Shingles, Rooflines Christmas Light Hooks (100-count)

Overall, the clips are very sturdy and work great for the off-the-shelf C9 lights, the kind that just press into a socket (not threaded). I purchased 300 of these for my Opticore lights that have the C9 size bulb with an E17 base and out of the 300, 32 of them broke and several of them cracked, see pictures. I tried to put them on carefully, I just don’t think they were designed for this size of base. However, I did test them on off the shelf lights and they do work great for those. It is also odd that they all broke on the same side. Maybe its’ a manufacturing issue?