Abstract: An improved lock mechanism for connecting an upper lid portion to a lower box portion is provided. The upper lid portion is provided with a locking pin extending downwardly from a lower surface of the upper lid portion. The lower box section has a vertical pin receiving socket extending from an opening in an upper surface of the lower box portion to receive the locking pin. The pin receiving socket opens into a horizontal slide bore extending from an opening in a front surface of the lower box section. A lock button, having a lock slot and a slide slot, is slidably disposed within the slide bore between a forward extended position and a depressed rearward position. A spring biases the lock button to the forward extended position. In the forward extended position, the lock slot secures the upper lid to the lower box by releasably engaging the enlarged head of the locking pin, which extends through the pin receiving socket into the slide bore.