LP4 to SATA 15pin Power cable
Ideal for small form factor desktop computers or servers that use Serial ATA Hard Drives
Connecting a Serial ATA Hard Drive to a standard internal Molex power supply connector – SATA (15-pin) to 4-pin Molex (LP4)
Appears to be around 16 or 18 ga. More than capable of handling inrush and constant current needed to run any PC accessory you'd see in a PC like a drive or tape.
The SATA end of the cable will only get +5 & +12 volts, SATA is supposed to have +3.3 volts, too, but the 4 pin connector does not have that. Lots of drives, etc. don't need +3.3 volts, like the CD/DVD/Blu-ray drive I will be using this for. Check the label on the drive to see if t needs 3.3