The Contour features an integrated rechargeable battery. TteSPORTS says it lasts for 10 hours, but in my experience, it seems to last a lot longer than that - I've only charged it once in the several weeks I've owned it. When you do need it, charging is handled with a standard Micro USB cable, included in the box.
This is exactly what I want from an MFi controller. No non-standard USB cable, no need to carry around extra batteries. The only thing that would make this better would be if it charged with a Lightning cable, but presumably this controller was designed before Apple allowed controllers to do this.