That is for screwing onto a Nectar Collector. I have no idea what they use to glue the quartz to the metal....
EU Drop downs: from the links posted, Vapefiend has the only one available that looks OK and they don't even ship to Spain any more... I'm sure that's working out great for them.
The only actual drop-down on Recommended Vape Supplies that's worth it is the tall S type, and is sold out.
The German site linked doesn't seem to have any kind of glassware like this.