Just to give you a perspective of how thin the drive is. The 7mm Seagate Laptop Thin SSHD is below the 5mm Seagate Laptop Ultrathin drive

Ultrabooks are slowly but surely becoming mainstream and we are always seeing slimmer ones each day. SSDs are the preferred choice of storage drives in Ultrabooks, but they also have the disadvantage of higher cost per GB when compared with a spinning magnetic drive. Not to mention the capacities aren’t that great either.

http://tech2.in.com/reviews/internal-drives/seagate-laptop-ultrathin-500gb-review/916054