A metric socket set is a collection of tools used for various mechanical and DIY tasks that involve tightening or loosening fasteners, such as bolts and nuts. Metric refers to the unit of measurement used in these tools, which is based on the metric system. This system uses millimeters (mm) as the primary unit of length, as opposed to the Imperial system that uses inches. A metric socket typically includes a range of sockets, extensions, and a ratcheting handle or wrench. Let’s check a few listed below: Extensions: Extensions are accessories that fit between the socket and the ratcheting handle. They provide extra length and are particularly useful when working in tight or hard-to-reach spaces. Extensions come in various lengths, allowing for greater flexibility in accessing fasteners. Ratcheting Handle: The ratcheting handle, also known as a ratchet or socket wrench, is the tool used to turn the socket. It features a mechanism that allows