The AMS1117 is a series of low dropout voltage regulators with a dropout voltage of 1.2 volts at a maximum current of 1 ampere. They are commonly used to regulate voltage in electronic circuits. The variants you mentioned (1.2/1.5/1.8/2.5/3.3/5V) refer to the output voltage options available for the AMS1117 series. They come in the SMD (Surface Mount Device) SOT-23 package, which is a small, surface-mount package commonly used in integrated circuits.
These voltage regulators are adjustable, meaning you can set the output voltage to any desired value within their specified range using external resistors. They are often used in applications where a stable voltage supply is required, such as in power supplies for microcontrollers, sensors, and other electronic components.