Product Name: Anti-Skimming Sleeve Case (Set of 5) Material: RFID Block & Shield Foil Shape: Sleeve type Size: 9 x 6.5 x 0.35cm Color: Glossy Gray This is an RFID & magnetic skimming prevention card case. It prevents unauthorized reading of card data, such as skimming. It also prevents damage to magnetic data caused by interference between cards from electromagnetic waves and magnetism.