USB (Universal Serial Bus) is the most widely used connector for connecting peripherals and accessories to a variety of devices; including computers, mobile phones, tablets and others. At present, the most commonly used generations of USB are 2.0, USB 3.0 and USB 3.1. The USB-C connector with a symmetrical shape is becoming more and more popular.
This is the rate at which data is written to or copied to and from a flash drive. It is given in MB/s (megabytes per second). High speeds are most important when writing or reading large volumes of data and the differences in speed with slower flash drives can be felt in the tens of minutes.
The lightning connector was developed by Apple and is used exclusively in its products, such as the iPhone, iPod and iPad. Like USB connectors, it is used to charge mobile devices and transfer data. It replaces older 30 pin connectors in products after 2012.
OTG USB flash drives have two connectors. One is the USB connector for connecting to the computer, and the other is for connecting to a mobile device. A micro USB or Lightning connector is used to connect to Apple products (iPhone, iPad, iPod).
The size (capacity) of a flash drive is given in gigabytes (GB). Typical sizes range from 4GB to 128GB, but more and more, models with a capacity of 256Gb or more are becomming available.