in March 2015. September 2014 saw SanDisk announce the first 512 GB SDXC card. 2016 Samsung announced the world's first EVO Plus 256 GB microSDXC card in May 2016, and in September 2016 Western Digital (SanDisk) announced that a prototype of the first 1 TB SDXC card would be demonstrated at Photokina. 2017 In August 2017, SanDisk launched a 400 GB microSDXC card. 2018 In January 2018, Integral Memory unveiled its 512 GB microSDXC card. In May 2018, PNY launched a 512 GB microSDXC card. In June 2018 Kingston announced its Canvas series of MicroSD cards which were capable of capacities up to 512 GB, in three variations, Select, Go!, and React. 2019 In February 2019, Micron and SanDisk unveiled their microSDXC cards of 1 TB capacity. 2019–present: SDUC The Secure Digital Ultra Capacity (SDUC) format supports cards up to 128 TB and offers speeds up to 985 MB/s. Capacity Secure Digital includes five card families available in three sizes. The five families are the original Standard-Capacity (SDSC), the High-Capacity (SDHC), the eXtended-Capacity (SDXC), the Ultra-Capacity (SDUC) and the SDIO, which combines input/output functions with data storage. The three form factors are the original size, the mini size, and the micro size. Electrically passive adapters allow a smaller card to fit and function in a device built for a larger card. The SD card's small footprint is an ideal storage medium for smaller, thinner, and more portable electronic devices. SD (SDSC) The second-generation Secure Digital (SDSC or Secure Digital Standard Capacity) card was developed to improve on the MultiMediaCard (MMC) standard, which continued to evolve, but in a different direction. Secure Digital changed the MMC design in several ways: Asymmetrical shape of the sides of the SD card prevent inserting it upside down (whereas an MMC goes in most of the way but makes no contact if inverted). Most SD cards are thick, compared to for MMCs. The SD specification defines a card called Thin SD with a thickness of 1.4 mm, but they occur only rarely, as the SDA went on to define even smaller form factors. The card's electrical contacts are recessed beneath the surface of the card, protecting them from contact with a user's fingers. The SD specification envisioned capacities and transfer rates exceeding those of MMC, and both of these functionalities have grown over time. For a comparison table, see below. While MMC uses a single