Be very careful buying any multi-disk eSata external drive enclosures for your laptop.
Many multi-disk enclosures require "port multiplier" (PM) support on their eSata connections but laptops (and desktop motherboards) rarely support PM.
I use single disk external eSata enclosures (WD mybooks) on my laptop that has an eSata port. I don't recall any problems with those simple enclosures. They may NOT support more than one volume on the drive but most people don't try to put multiple partitions on single disk externals.