It is the FreeStyle Libre, which has a small needle and a radio. The provided reader is not the most accurate, but you can read the results with any NFC enabled device. For Android xDrip plus is my choice and I've already contributed new features.
A disclaimer: do not use any of these if you don't know exactly what you're doing. If you do acknowledge the risks and have some backup system for measurements, this system is making the life of a type 1 diabetic much easier...
IIRC, you're not even supposed to rely on the Freestyle Libre exclusively, you've still to take the traditional finger pricks reasonably frequently to be sure its calibration isn't wrong.
I know that. But with calibrations xDrip can adjust its values which is not possible with the official device. For me it is enough to test from fingers about twice per week.
A disclaimer: do not use any of these if you don't know exactly what you're doing. If you do acknowledge the risks and have some backup system for measurements, this system is making the life of a type 1 diabetic much easier...