Sininen keittiö (blue kitchen) features blue flower decorations with blue lines. Decorations like this have traditionally been used in kitchenware. One of the decorations used in the Domino white series.
A jar is a container that can be used for long-term storing of foods and drinks. You can also use it for interior decoration. For example, you could put in some flowers, your favorite sweets, stationery and so on.