During the hot summer months in Japan, company co-workers often head out to beer gardens after work. But all too frequently, heavy-drinking bosses try to refill glasses and keep everyone on the same page, in terms of drinks consumed.
Here's a product designed to foil such antics. It's a plastic beer mug that looks like it's full of beer. A special ink inside the plastic becomes yellow when the mug is filled with ice water, making it appear that the mug is full of beer.
The product is called “USO Beer” (fake beer). Cocktail glass and wine glass models are also available.
HERE is a video demonstration
To be honest, the color does not entirely resemble the pale yellow tints of lager beer. But perhaps the busy boss will not even notice.