An SD (Secure Digital) card and a flash drive are both types of storage media, but they have some key differences. An SD card is typically used in digital cameras, smartphones, or tablets to store photos and videos. Flash drives are smaller than SD cards and usually use a USB port for connection. They're commonly used for transferring data between computers, as well as storing documents, music files, and other data. One major difference between the two is that an SD card uses non-volatile memory technology which means it doesn't require power to retain its contents while a flash drive does require power to keep its information stored when not connected to a computer. Additionally, an SD card often has higher read/write speeds compared to most USB flash drives making them ideal for quick transfers of large amounts of data such as HD video files or thousands of pictures.