Soap box for a big soap

I often use a large soap 250g in traveling. I can not buy a soap dish of this size. The soap measuring 115 x 72 x 40 mm. The design is simple. The cover has a gap of 1 mm. At the base there is a half protruding ball to lock the cover. The parts fit together well without post processing. It was necessary to lightly sand the half ball.