Genuine Lenovo chargers and ac adapters are listed below, you can browse by the laptop series, just simply click your series if known to you and this will then show you all the Lenovo laptop, notebook and chromebook models, along with the recommended charging unit for your machine or if you know the part number of your Lenovo ac adapter you can simply click on the part numbers section.

Also for ease of finding, if you know your exact Lenovo power adapter specification, then scroll to the bottom and you will find all the common Lenovo charger power units listed by voltage and amp, from the small 45w round tip to the 230w slim tip or any of the USB type C versions.