A USB flash rive is a NAND-type flash memory data storage device integrated with a USB (universal serial bus) connector. USB flash drives are typically removable and rewritable, much shorter than a floppy disk (1-4 inches or 25-102 mm), and weigh less than 2 ounces (56 g). Storage capacities typically range from 64 MB to 32 GB or more. Some allow 1 million write or erase cycles and have 10-year data retention, connected by USB 1.1 or USB 2.0 or both. USB Memory card readers are also available, whereby rather than being built-in, the memory is a removable flash memory card housed in what is otherwise a regular USB flash drive, as described below.