Credit Card Sleeve: RFID Blocking, Leather, & Secure Options Idiom of the Day: "To Have a Card Up One's Sleeve" , This idiom means to have a secret plan, advantage, or resource that you can use when needed, especially in a tricky situation. It refers to Silk Printing Hard Plastic ABS RFID Blocking Card Sleeve for Credit Card RFID Blocking Card and Rrid Shielding Holder price Made in China.com Credit Card Sleeve with RFID Protection