The HP 840744-001 power button board and cable is a replacement assembly for the power-button function in supported 15-inch HP notebook models. It brings the board and its connector cable together as one part for service or repair.
The listing associates this part with HP ProBook 650 G2 and G3, and 655 G2 and G3 notebooks. Its stated fit is for 15-inch models, which distinguishes it from parts intended for other product sizes.
The connector cable is included with the board, so the assembly contains both components named in the part description. Use it as the power-button board assembly for the listed model families.