The LED lining needs to be bonded with CA glue and polished to be flush with the back of the casing. Without glue, the ESP will overheat, and if printed with PLA, the top will open. I used these on a FluidPi on a 2ender 3v2. You need to pry off the green glue that locks the lens rotation. Just carefully clamp it with a pointed pliers and use another pair of pliers to swing the lens. It takes about 1/8 to ¼ turn