Free Space adds a minimalistic widget in Today Notification Center, so you will be able to quickly check free storage space on your Mac. Just in one click!
Free Space also shows free space on external devices like Transcend JetDrive, usb flash drive or usb ssd, etc.
The widget takes up little space — just one line — and it can show free disk space on up to 4 devices.
On the screenshot you can see Free Space widget that shows how much storage space I have on my Mac: SSD and JetDrive.