What race crown for a 3T Exloro fork?
When I looked at their site, 3T didn't call out numbers for the fork, but it would appear the frameset uses one of the more common contermporary setups, IS52 for the frame and therefore a crown race that Cane Creek describes as 52/40, the 40 being the OD classification of the crown race seat under SHIS nomenclature. Crown races like that are basically all the same and interchangeable, because they live in a world where they have to be stand-ins for forks that have integrated crown races, which are headset-brand-neutral. So if the above assumptions about your frameset are true, you're safe using whatever 52/40 crown race you can get your hands on, but the Cane Creek one that should match is their part number BAA0173A.