The Lenovo 5A10H03910 is a laptop AC adapter for powering a compatible laptop. This part number identifies the Liteon ADLX45DLC3A model among Lenovo adapters with similar output ratings.
It supplies 20V at 2.25A, with a rated output of 45W, and connects through a Slim Tip connector. Check that the laptop uses this connector and power specification when choosing a replacement.
The included 0.5m power cord makes the adapter suitable as a replacement or an additional power source for a compatible setup, such as a desk or another work area.