INTRODUCTORY PRICE! Try STËLZ Hard Seltzer Mango! A fresh and fruity drink with a kick. Our hard seltzer is made of sparkling water, a hint of mango and 4.5% alcohol. 63 calories, no sugar, no gluten and no carbs: that’s how this hit from the US is now taking the Netherlands by storm. The refreshing alternative for beer, wine and cocktails.