The SLAB_USBtoUART is a USB to Serial device. SLAB is short for SILABS,the chip inside of this device.
Drivers:
linux 2.6.x : linux_2-6-x_vcp_driver_source
Linux 3.x.x : linux_3-x-x_vcp_driver_source
windows CE 6.0: vcp_wince60
Windows CE 5.0 : vcp_wince50
Macintosh OSX (v4):mac_osx_vcp_driver(confirmed to work with macOSSierra)
Windows 2K ServerDownload VCP (4.79 MB):cp210x_vcp_win2k-exe
Windows XP/Server 2003/Vista/7/8/8.1 Download VCP (3.66 MB):cp210x_vcp_windows
Windows 7/8/8.1/10 Download VCP with Serial Enumeration: cp210x_windows_drivers_with_serial_enumeration
Windows 7/8/8.1/10 Download VCP (5.3 MB): cp210x_windows_drivers
On OSX / Linux you may find the device listed under /dev/tty.SLAB_USBtoUART or /dev/cu.SLAB_USBtoUART
If you are installing these drivers as part of a Pulse Oximeter, you should check outthis post which gives a little more info for that domain.
Unsure what operating system you have? Check out http://whatsmyos.com/
The drivers listed above are sourced from Silicon Labs. They are kept here as a mirror of the silicon labs driver page. I will do my very best so that any links to this site will not be broken. Questions or Answers? Please comment below.