MPERO Collection Tough Armor Credit Card Black Case for Samsung Galaxy S4 Rear hidden compartment allows for the storage of a single credit card and drivers license for easy transportation and concealment. Specifically designed to protect your device from harder drops and accidental tumbles. Made from an inner shock resistant TPU core and reinforced with an outer hard plastic rear shield. Precise cut-outs for given ports thus keeping functionality to a maximum. MPERO is a protected trademark.