Which torx for e6440 cpu replace?

Hi all,

The parts-people video on upgrading the cpu on the e6440 clearly shows a torx screw holding it in place, yet neither they nor the Dell manual for that model mention this as a necessary tool for the job. One other video states it's a T6, but i find it hard to believe it is this small. I have a processor upgrade on the way and need to know what i need for this removal please? My incomplete set (didn't plan to use them again after i left Apple laptops) includes T7,8,& 9. Close enough? Thanks!