Box with component internally housed

A box comprising:

• a first cover made of resin, including a front wall, an upper wall extending from an upper side of the front wall, a lower wall extending from a lower side of the front wall, and a pair of side walls extending from opposite longitudinal sides of the front wall, which connect the upper wall to the lower wall, thereby forming a generally rectangular shape;
• a second cover made of resin and configured to fit to the first cover, the second cover including a base plate;
• and
• an interior component fixed to an interior side of the base plate so as to be housed in an internal space formed when the first cover and second cover are fit to each other,
• wherein the first cover includes an engaging portion disposed at an edge of the upper side of the front wall and a retaining portion disposed at the lower side of the front wall, and the second cover includes an engaged portion at an uppermost end of the base plate and a retained portion at the lower end of the base plate,
• wherein the first cover and the second cover are configured such that the first cover fits to the second cover by (1) engaging the engaging portion of the first cover with the engaged portion of the second cover, (2) rotating the first cover about the engaging portion which is engaged with the engaged portion so that the retaining portion approaches the retained portion, and then (3) retaining the retaining portion of the first cover with the retained portion of the second cover, and
• wherein a projection extends from the engaging portion, the engaging portion is configured to slide over and overlap an outer surface of the uppermost end of the base plate so as to engage the engaged portion, and the projection is configured to form a gap between a front edge of the upper wall of the first cover and the uppermost end of the base plate of the second cover when the projection abuts the uppermost end of the base plate while the retaining portion of the first cover is normally retained to the retained portion of the second cover, the gap through which the interior component housed in the internal space can be seen from the outside of the box.