Review on Bright Eyes 3-Pack: Clear and Red Diffuser Lens for 1200 Lumen Rechargeable Bike Lights and More by Elvis Kohl

. and a postage paid envelope for me to send my light back. The diffuser of the replacement lamp fits exactly. The diffuser was installed with convex protrusions out and smooth side in. Also, the green O-ring must be on the outside of the lens. I might have had an o-ring in it, but I've tried both. ----------------------- I have 2 packs but I only use one on my handlebar mounted light. I leave my helmet lamp as a place for a longer throw. The wide-angle beam was great for a handlebar-mounted light. I was able to use a light (Bright-Eyes 1200lm) on low/medium (800lm) for climbing without a light on the helmet. After descending, I turned the light to maximum, tilted it a little, put a lantern on the helmet and could see everything. FYI, the diameter of the lens is approximately 39mm.