The invention provides a three-dimensional structure having at least one structure surface, the structure being adapted to be attached to an apertured surface with the structure surface facing the apertured surface; and a curved hook element having a base and a distal end, the distal end of the hook element being adapted for insertion into an aperture in the apertured surface, and the base of the curved hook element being slidably affixed to the structure surface of the three-dimensional structure such that movement of the base is constrained along a line within the structure surface. The device can be used in a method of attachment onto an apertured surface, in particular the inner surface of an automatic laundry washing machine drum, and is particularly suitable for dispensing rinse additives into the rinse cycle of an automatic washing machine.