Premium Power Products compatible laptop battery for Lenovo ThinkPad E40. Replaces 42T4235, 42T4702, 42T4703, 42T4731, 42T4733, 42T4737, 42T4751, 42T4752, 42T4753, 42T4755, 42T4756, 42T4791, 42T4793, 42T4795, 42T4796, 42T4797, 42T4817, 42T4819, 51J0499, 57Y4185. Li-Ion, 11.1 Volts, 4800 mAh, 6 cell, Black.