Basically my guess is your actually buying from the factory.
Same place also does complete REAR indicators - but you need the OEM bulb-holder insert. The after-market "spring contact metal" isn't and doesn't. And the lens screws are not Stainless. But 28Euros a pair shipped it is a small price to pay. Just swap them over. Only required if you break the OEM one or decide to get inventive. I may need to get inventive AGAIN soon - short stems

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ime - Clear lenses do not work as well as dark if you live somewhere VERY sunny. Basically they wash out. Dark lenses do reduce lumens a bit but provide better contrast. Dark ones DO fade paler in the sun over time. If you want to be seen - Amber LEDS (big ones) behind amber lenses work best. I use 10W amber LEDs behind smoked lenses.