SATA power adapter cable uses a splitter mode to convert Heavy duty splitter with 4-pin (male )to 2 SATA 15-pin(female). This makes the computer power supply without a SATA power plug, can supply power to 2 SATA interface hard drives and optical drives at the same.
Sata power adapter uses the spare power to turn the large 4p port of the chassis power supply into 2 SATA hard disk power supply ports.