Securely erasing hard drives is not as easy as simply reformatting them. Tools such as this StarTech Hard Drive Eraser can get the job done in a secure fashion. It can erase up to 4 SATA drives simultaneously. It has 9 erase modes, including Single Pass Overwrite and Multi-pass Overwrites.
The device comes with a LCD screen and doesn’t require a computer to work. It lets you print logs upon job completion.