Restore portable operation on compatible notebooks with a lithium-ion battery configured at 7.72 V and four cells. This replacement targets systems that call for L82391-006 or HK04054XL-PL, giving technicians a clearly matched battery option when the installed pack carries either reference. Battery Technology HK04XL-BTI combines the supplied 4-cell configuration with a 7.72 V electrical rating. Those details matter when replacing a notebook battery: the replacement must match the system's battery reference and electrical requirements rather than only resembling the installed pack. The lithium-ion chemistry identifies the battery technology used by this replacement. Use this battery for service work on notebooks where the existing battery label or system requirements identify L82391-006 or HK04054XL-PL. Compare the reference on the removed battery with the required replacement reference before installation. The four-cell design and 7.72 V rating provide concrete identification points alongside the cross-reference numbers, helping distinguish this pack from batteries intended for other notebook configurations.