Sorry don't know offhand what size it is you need, but torx is torx, no metric or imperial required. T-10, T-15, T-45, up to at least T-60.
Do yourself a favour though if you buy a set, and get Torx Plus, they fit & drive far nicer as I just found out. Brake job on father in law's 98 Lumina. Seized T-55's hold the caliper carriers on :roll: