Drive flange bolt head size ?

[Davetom]

Hi all, what socket do I need to undo the 6 bolts on the driveshaft flange please ?
Found lots of pics online of new ones but none mention the head . It’s a female similar to TX type but not actually TX .
Thanks

 

[DXX]

XZN or often referred to as triple square spline. I can’t advise what size but it’s worth buying a good quality set, very common on auto equipment.