Great little accessory from Recta / Victorinox, best used in conjunction with a SAK case, but can be used as a stand alone accessory.
It features the following
Rulers in cm and inches
2 spirit levels, a bubble on top of the compass, and one when the tool is turned on the side, there is a notch where the bubble settles when level.
Made by Recta a well known compass manufacturer.
Coming in at about £16 its a nice little tool and covers a lot of bases.
Works great with case.