The suit, filed by Stacy Pincus, claims that while Starbucks (SBUX) advertises its cold drinks by fluid ounce, the numbers are only accurate when ice is added to a drink.

“Starbucks is advertising the size of its Cold Drink cups on its menu, rather than the amount of fluid a customer will receive when they purchase a Cold Drink — and deceiving its customers in the process,” the suit says.

A Venti cold drink, for example, is advertised as having 24 fluid ounces, but only includes 14 ounces of the actual liquid, the lawsuit claims. The rest is ice.