That looks like the "split2g" variant of VMDK. That's where you have a fixed allocation (preallocated) disk which is split into 2GB extents primarily so that the image can be transported on FAT formatted drives. Typically this variant consists of a small descriptor .vmdk file - if you examine this you'll find that it's just a text file which lists the 2gb extent files, in order. Then you'll have N 2GB extents, plus an optional final extent smaller than 2GB, holding the residue of the image. In your case I see a couple of odd sized files, so I think perhaps this drive has been increased in capacity a couple of times (quite common, since preallocated a.k.a. fixed drives are invariably created too small).
VirtualBox supports this VMDK variant: just copy the entire set of files as a block, when mounting the image you select the control file (the small one which doesn't have the -snnn suffix).
The files which do not have a .vmdk extension are superfluous - not usable in VirtualBox. You'll have to create the VM from scratch, select "choose existing" when you come to the drive step. It's best to have the drive image inside the VM folder so that you don't have bits of VM scattered in odd places.
Personally I think a single file is more elegant, and a preallocated disk is just a waste of host space. I would convert it to a dynamic VDI before I used this image in VirtualBox. That's what you'll get if you clone this VMDK using CloneVDI
. If you prefer a command line app then you can also use "VBoxManage clonehd ..." - the command syntax is given in the user manual.