Hello!
This may be what you're after: FX6 22mm 6V - 8.4V 5A 4-Mode Driver Circuit Board for Cree XHP50 / XHP70 / MT-G2
Recommended reading: 2 Li-ion 3 amp Driver Super Output Current Mod "Now with Larger Toroid driving a MT-G2" -> I am doing my own mod on one of these. Got mine here.
Cheers ^:)