Need an AC Adapter for the Lenovo-IBM Thinkpad X40-2371? BTI has you covered with our 20 volt 4.5 Amp AC Adapter. Our power adapter products are engineered to meet or exceed the original manufacturer"s specifications and this BTI product replaces the original Lenovo-IBM AC Adapter. All BTI power adapters are manufactured and tested under our stringent quality standards and come with our industry leading 24 month warranty. BTI.. Powering your mobile life.