5 Pack Specialist ID Multiple Card ID Badge Holders - Heavy Duty Rigid / Hard Plastic (Black) Securely Holds One Standard 30 Mil Card (Credit Card Size) on Front Securely Holds One or Two Standard 30 Mil Cards in Back (Or One Thicker Card Such as a Clamshell Prox Card) Opposing Pressure Keeps Cards Snug and Tight Inside Ideal for Cards That Do Not Need to be Removed Often All in One Solution for Work. Keep Your ID Prox Card in Front and a Credit Card in the Back for Lunch Time