... Diameter: 2.5mm 4.External Diameter: 5.5mm SpecificationReplacement Laptop adapter for Thinkpad 16V 3.5A AC AdapterInput: AC100 ... Part Number02K6543, 02K6555, 02K6545, 02K6548, 02K6549, 02K6550, 02K6553, 02K655Fit Laptop ModelThinkPad 240, 310, 360, 380, 385XD, 390, 390E, 385XD, ... 770, ThinkPad 600, 600E, 600X, Thinkpad 500, 560, 570ThinkPad A20, A20M, A21, ...