MX DC Female Connector Chassis Type 2.1mm x 5.5mm (MX-2248)

2.1mm x 5.5mm is the single most common DC barrel size across hobby electronics, routers, and small appliances, which makes this connector the default choice whenever a project's enclosure needs a permanent, panel-mounted power entry point rather than a cable running loose through the wall. It mounts through a single drilled hole with a nut on the outside, and the inside tabs take a soldered or crimped connection straight to the board or wiring harness. Fitting one of these means any standard wall adapter built to this size - which is most of them - plugs straight in without needing an adapter tip or a non-standard connector swap.