The press-in area comprises an interior bar (62) bounding the opening, and an external bar (63).

The bottom may include an inner ridge (42) parallel and relatively nearer edges of the bottom than the disposal of the outer ridge on the edges of the top.

The storage device may be stacked by cooperation of the inner ridge on the bottom of the storage device with an outer ridge on the top of the other.

serrated lock washer with external teeth

Each rib defines rib edges (24).

The rib (24) comprises a rib body (30) and a series of rib feet (32).

Each ridge defines with the adjacent ridge a groove (5).

Each of the recesses (44, 54, 64, 74) defines a lower rib (45) and an upper rib (46).

The barrier rib includes a transverse barrier rib and a longitudinal barrier rib crossing each other.

The annular rib (34) comprises a ribless portion (35) for guiding the helical rib that has reached the annular rib to the housing portion.

The small tube (10) is in particular arranged radially and its outer end is even with the outer surface of appendix (7).

A channel rib is formed on each tubes and a crevice rib over the center leg forms a third rib.

The first rib is twisted from a base end of the first rib to a tip end of the first rib.

Into each recess is inserted a shaping rib (15) which completes the rib bearer (13) to form a rib.

A second rib (43, 44) extends substantially perpendicularly from the second surface, and the second rib is substantially aligned with the first rib and positioned substantially opposite the area of discontinuity of the first rib.