... 2.Power: 56W 3.Internal Diameter: 2.5mm 4.External Diameter: 5.5mm SpecificationReplacement Laptop adapter for Thinkpad 16V 3.5A AC AdapterInput ... , R33, ThinkPad T20, T21, T22, T23, T24, T30, T40, T41ThinkPad X20, X21, X22, X23, X30, X31, X40ThinkPad i1200 Series, i1300 Series, i1400 Series, i1500 Series, i1700 Series