what they sell is a custom type of absinthe glass termed the Slipstream — a drinking absinthe glass that can retain i.e.and cold water in one chamber situated above sugar in another, and the absinthe in another chamber beneath that, all connected to a glass straw. it’s a clever device that facilitates what absinthe aficionados call the louche, a methods by which the alcohol-soluble herbs such as absinthe glass anise and fennel and oils of wormwood, are slowly drawn out by cold water and emulsification.