The Dell 451-BCBL is a four-cell battery for notebook computers, intended to power a compatible laptop away from an external power source. Its stated energy capacity is 56 Wh.
The datasheet identifies lithium-polymer chemistry and specifies 15.2 V and 3600 mAh. These electrical details can help distinguish the battery pack when checking a replacement.
Associated OEM references are 7FHHV, J9NH2, 99NF2, and 0W7NKD. The product information does not identify specific compatible laptop models.