The buttonless touchpad first appeared on the X220 and X1 (and possibly some IdeaPads) and is missing buttons bellow the trackpad. The trackpad can be pushed for a pysical click, pivoting from the top. There is only one switch so the middle and right click must be configured by driver software.
All functionality should work out of the box apart from possibly right click.
Arch Linux has a version of xf86-input-synaptics in the AUR compiled for "clickpads" called xf86-input-synaptics-clickpad