I don't know what size but on an 01 S60 you need an Allen wrench.
It should be a 3/8" Allen wrench.
Lug Wrench to remove tire & Wheel Socket Wrench or Hex Wrench to remove Caliper bolts Large "C" clamp to collapse caliper piston Rags, and a good spray brake cleaner
the caliper bolts require a 3/8" Allen wrench. You can buy these as a socket at just about any parts store.
It takes a T55 Torx bit on the front calipers.
I'm pretty sure that takes a 7mm Allen key.
You need a 3/8" allan key or hex socket - not a torx
Metric Allen wrench.
You need a 15 mm regular wrench.
It will be a 14 or 17 mm wrench.
45t
use an Allen wrench not a socket or open or box wrench.
14 mm