Our website provided a free download of VBoxRawdisk 1.3.7 for Mac. The actual developer of this free software for Mac is WhatRoute.
From the developer:
VBoxRawdisk helps you generate the raw disk (VMDK) file required to load a real disk drive into VirtualBox. When the utility is initiated, it scans the physical drives attached to your Mac and presents a table similar to that used by Disk Utility. When a drive is selected, key attributes of that device are displayed, enabling you to determine which drive contains the data you wish to use in VirtualBox.