Inspecting a figure 8 belay device

[Mika]

Thanks @Jonny and @surveyor for all the stimulus! I'll definitely look into rope wrenches

I also wanted to mention that I heard back from the manufacturer of my figure 8 device (Alpen Pass), and they said the marks were machine marks indeed. They even shared (unsolicited) what I understood to be the reports from break tests. I'm in no position judge such documents, but I can't see why they'd fake transparency.