I second what Raf says. Garrett (terminal fettler) makes probably the best rf topper available. I have one and its a thing of beauty, you can just barely see any seems on it and everything fits together like a glove.
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And like Raf say about the lighting of the Perspex, they used incandescent light bulbs. Fiber optics would fit but light it correctly, and I haven't seen an LED that would work because the light source has to be in the middle of the Perspex piece. And since the lights are underpowered (the correct grain of wheat bulbs are 12v dc), they are less bright than an LED or fiber optic would be.
I have a post in the cargo hold that shows the kit I sell for the terminal fettler rf topper with the correct GOW bulbs. The post also has a few videos showing the kit installed and lighting up my ESB TF topper.