Lenovo ThinkPad X61 100-240V~1.2A 90W AC Adapter 42T4438.Model Number: 42T4438Lenovo Part Number: 42T4438Compatible Part Numbers: 42T4439 36200150Compatible Models: Lenovo ThinkPad X61, Edge E420sSpecifications:Input: 100-240V~1.2A50/60Hz Output: 20V - 4.5ATotal Output: 90W