Jack (female side): Outer dimensions 5.5mm x 2.1mm Plug (male) side: 9 types 2.5/0.7, 3.5/1.35, 4.0/1.7, 4.8/1.7, 5.5/1.7, 5.5/2.1, 5.5/2.5, 6.3/3.0, 6.0/4.4 mm Plug size conversion is possible by inserting into the jack (female side). Plug size conversion is possible by connecting various plugs (9 types) to the jack (female side).