A memory card used to add nonvolatile digital storage to portable devices such as smartphones, tablets, and laptops. Originally developed in 1999, SD cards now come in four different families, based on capacity and capability, and three sizes. They are frequently used with smartphones as a way to increase data storage, and with digital cameras as a means of storing photographs. The highest capacity standard supports cards capable of storing 2 TB, but the largest capacity card available in 2019 stores only 512 GB (one quarter of the maximum possible) although a 1 TB prototype has been revealed.