With the growing amount of data and information, there is an essential need for memory cards for the purpose of storage. To retrieve back the data stored in the card, card readers are used. It acts as an interface between the system and memory card. It has got an usb (universal serial bus) port to connect with the system. Small slot is provided to insert the card. The function of it is similar to pen drive except it has a slot to insert the memory card. They are available for different types of cards such as Compact Flash (CF), Secure Digital (SD), Multi Media Card (MMC) etc. Apart from reading the contents of the card, they also offer write capability to write data or information to the card. Single card reader could have various slots for different size of cards. Or it could have single slot that would be compatible with different size of cards.

Some card readers could support up to 25 different memory card formats. These could remain connected to the system permanently. Thus it saves our time searching and connecting them during each and every usage. Another advantage is that it also save the battery of cameras or mobile phone as it is not required to be powered on while transferring. It is also very compact and light weighed. So it does not occupy much room. It is easy to insert and remove the cards in respective slot. When the card is inserted correctly LED turns green otherwise it would be in red. When the card is inserted correctly, new removable drive shows up in driver?s list. It is now possible to insert/delete/move the contents of memory card. They are available at a low cost and easily available in the market. Thus the card readers are used for quick, hassle free transfer of data between the system and memory card.