It's uncommon, indicated by the little diamond in the lower right-hand corner.

A circle means common, diamond means uncommon, star means rare, and a silver star means very rare.
Here is a list of all Steam Siege dual-type cards, including Shiftry, Volcarona, Volcanion, Galvantula, Bisharp, Mega Steelix EX, and Mega Gardevoir EX.
Also I want to say that that card looks awesome af.