Weizenbier is a very old style, originating from germanic tribal times.
It predates Pilsner by centuries. It is a bit thicker because of less filtering than others. And has a much shorter shelf-life than highly filtered styles.
The name Weisse / Weissbier / Whitebeer is in comparison to historically very dark beers.

This is general info about Weissbier.

Here you can buy Alpirsbacher.

EDIT But mind the special way to pour it in your glass

No idea of the detailed taste of this brand, Fellfrosch might elaborate. I prefer "Helles" because i can drink much more of it. With Weissbier i feel full after two bottles, also the noticeable yeast taste is not mine.