... 5mm 4.External Diameter: 5.5mm SpecificationReplacement Laptop adapter for Thinkpad 16V 3.5A AC AdapterInput: AC100-240V (worldwide use) ... 310, 360, 380, 385XD, 390, 390E, 385XD, 770, ThinkPad 600, 600E, 600X, Thinkpad 500, 560, 570ThinkPad A20, A20M, A21, A22, A22M, A30 ... , A31, A31PThinkPad R30, R31, R32, R33, ThinkPad T20, T21, T22, T23, T24, T30, T40, T41ThinkPad X20, X21, X22, X23, X30, X31 ...