just recieved the nockturnals and the work flawless. No glue, No Tabs, NO wiggling, fits carbon, fits uni nocks, They don't slide in and out, Don't get lose and fly out. Easy insert on shaft draw back and release and instant very bright light, easy to turn off with a small wire or ball point pen. Then Repeat. Works everytime. I would highly recommend these. Currently making my own matched weight nocks so i can practice without using them. Also only 20 grains. Only down side is the don't have replaceable batteries but there $ 25 for 3 with i think 5 colors to choose from. Great product