The fourth lower flat support portion 349 may be shorter than the first lower flat support portion 319, such that the fourth lower flat support portion 349 does not extend further than a terminal end of the fourth lower flat support portion 257 (e.g., is coplanar with) or extends a smaller distance from the terminal end of the fourth lower flat support portion 257 than the first lower flat support portion 319 extends from the terminal end of the first lower flat portion 251. The receiving groove GV may not be provided in the fourth lower flat support portion 349. That is, the fourth lower flat support portion 349 may have substantially a same thickness as each of the fourth upper flat support portion 341, the fourth upper bent support portion 343, the fourth extending flat support portion 345 and the fourth lower bent support portion 347.
The second support member 320 and the third support member 330 may have substantially the same shape as the fourth support member 340.