The Dell YGT77 is a 65 W AC adapter for powering a compatible laptop, with an output of 19.5 V. It converts AC input to DC power; check that the laptop supports these output specifications and connector.
Its slim design and round plug with a central pin identify this version. The plug measures 7.4 mm in outer diameter and 5.0 mm inside, helping distinguish it from Dell adapters with other plug sizes.
Package contents: a three-pole C5 power cable is included, according to the listing.