You are buying the printed battery cover only no calculator.  3D print items that I design and print. 

 The item will be printed in black PLA filament. For the contact plate, you will need a metal plate 27mm x 5.5mm x .5mm and two large solder points where the batteries touch the plate. Trimming the plastic corners a little for a perfect finish.  Please let me know if you have any questions. Thank you