This Sabrent OTG card reader is no bigger than a standard USB flash drive. One end has a USB 3.0 Type-C port and the other end has a USB 3.0 Type A port. Both sides include caps so they're ...

SD cards were first available in 1999 from Panasonic, Toshiba and SanDisk and are the largest type of SD card. A normal SD card is 32mm long by 24mm wide by 2.1mm thick. It will weigh about two grams.