"A cover 350, being made of transparent resin such as polycarbonate, polystyrene, and AS resin, has an upper wall portion 351 covering the top of the storage case body 341, cover side wall portions 352 and 352 which are provided upright on ends of both sides and are in close contact with the inside of the case rear wall portion 345, and a cover rear wall portion 353 which is provided upright on the" . . . .