It's a power cable adapter.
Great price. Eliminates lots of clutter when using SATA drive with older power supply. With both plugs combined it stays connected to drive better as well.
Good approach to convert older PC power supplies to power SATA HDD. Better fit using this than seperate power and data cables.
Easy and quickly bought my TV component and used tutorial to fix. Now have a working TV again for a tiny fraction of cost of a new TV, so very satisfied.