Unless you can find someone who has used that specific brand, you won't know for sure, but I would guess that this is poorly constructed junk made of poor raw materials.

If you keep watching ebay for Bosch or Hella as well as the classified sections of this and other MB enthusiast forums, you will eventually find quality built units for reasonable money. I did, I got my entire setup including vac level control switch and trim panel from a wrecked Euro car for $250. I had to buy one lens, but I still didn't go much over $300. I now have high quality, very functional euro lights.

BTW, if you don't live in snow country, the wipers are not useful. I have driven in bad snowy conditions that coat the lights with grime. The wipers with their squirters clear off the lights quickly and without having to get out in the weather to wipe them manually. Under these conditions, the wipers are EXTREMELY useful. Believe me the Germans did not put them on there for looks.

When I lived in Germany many years ago, in the Winter I had to stop at rest stops along the Autobahn to use snow to clean the headlights so I could see where I was going. It was these driving conditions that led to this useful addition. In later cars they rely on a pressurized stream of heated liquid.

Be patient and you will find some quality units for a reasonable price. Put a WTB add in the parts section of this forum. Since this is Summer with the long days, can't you make it a few months with what you have?

Good luck,