... .5mm 4.External Diameter: 5.5mm SpecificationReplacement Laptop adapter for Thinkpad 16V 3.5A AC AdapterInput: AC100-240V (worldwide use)Output: DC16V ... 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 ...