Does True Image 2016 use Microsoft VSS or it's own version of a VSS

I use both Reflect and True Image 2016.  With both I back up to an external USB 3.0 Western Digital 4TB with 2.11TB free space.  True Image works well the external disk being backed up to, does not do any thrashing.  When I use the most current version of Reflect it beats the heck out of the head on the external drive (it did it on older versions also).

I thought maybe Reflect had the VSS on the external and had to read it, then go read from source and write on WD external?  But my question for this forum is does True Image 2016 use a VSS and if so does it use Microsoft or it's own version of VSS?   Whatever Acronis uses, it is a lot easier on the external drive than Reflect.