HP 840752-001 top cover is a replacement notebook upper cover for selected 15-inch HP ProBook models. This specific 4-button version is intended for systems with a touchpad and pointing stick.
The service guide identifies the TouchPad as part of the top-cover kit. The cover provides the upper case area around these pointing controls, making it a relevant service part when that assembly needs replacement.
It is listed for certain ProBook 650 and 655 models in the G2 and G3 series.