Flashlight lenses for Halo Mjolnir helmets. Use your slicer to scale them to fit.

I designed these for Rainyfire's helmet (scaled up to 107% in my case): https://www.thingiverse.com/thing:2739764

You'll probably want to use a resin printer for this. I used a Mars 2 with Anycubic Clear resin at 0.02mm layer heights. Clean well, cure for 1-2m under water and finish with some clear coat spray.