There are a amount of on the card, which will soon be dry after cleaning, so you don't have to wait too long to use the card reader normally. According to the degree of the card, each card can be cleaned more than one card reader. Level: 3.375 inches, width: 2.125 inches, thickness: 0.03 inches (standard credit card thickness, if the cleaning card is too thick, it will not be put in the card printer/card reader). Just open the package, remove the cleaning card from the bag, and then put the cleaning card into a card reader like a credit card. After the first cleaning is completed, turn the card over and slide repeatedly to that everything is very clean. Compatible with most card , card printers and magnetic bar . Effectively remove the dirt and magnetic oxides on all card , hotel magnetic key locks, credit card machines, automatic vending machines and optical card . It is recommended to use it regularly once a week to prevent preventive maintenance of the card reader to effectively extend the service life of the card reader. With it, you don't need to directly replace the card reader. You only need to use our products for cleaning, which can solve the problem that cannot be effectively read and reduce the error of chip card reader. Material: plastic colour: White Package Contents: 50 sheet x card swiper Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.