HP 919701-850 is a replacement lithium-ion battery for selected HP laptops, supplying power when the computer is away from its adapter. Its four-cell configuration is listed for HP 14-bw0xx, 14g-bx0xx and 14q-by0xx laptop families, where the guide describes battery replacement as customer self-repair.
The battery is rated at 41 Whr and 2.8 Ah. These specifications identify this part; HP 919700-850 is a different three-cell, 31-Whr option. Check that the laptop configuration calls for the 919701-850 before choosing it for service.