30-377 is a chassis mount coax power jack designed for DC power connections in electronic equipment. It features a 2.1mm inner diameter and 5.5mm outer diameter configuration, which is a common standard for DC power applications. The jack mounts in a 7/16" diameter hole and accommodates panels up to 3/16" thick. This Japanese-style power jack is ideal for use in audio/video equipment, consumer electronics, and other devices requiring reliable DC power input connections.