A structure for measuring iron loss of a motor stator core is provided. The juvenile seat also includes a height-adjustment mechanism coupled to the headrest for up and down movement with the headrest to adjust the height of the headrest above the bottom seat portion. The composition contains a cosmetic stick composition, a green soap solution, rubbing alcohol, and water. An inner sidewall of each passageway has a protrusion extending into the receiving space to limit a movement of the contact, such that the contact can float upwardly and downwardly in the vertical direction without being drawn out of the passageway.