Bizarrely they don't do all thicknesses in all couloirs!
I have 3mm black on the racks (with a sacrificial extra ring taped on at each end made from offcuts) and 2.5mm blue on the decks - both absolutely fine so far except for one point where I didn't quite glue a blue edge. My fault not the material.
But I think 2.5mm black is one they don't make.
Probably suggest 3mm rather than 2 - or am I just trying to make Usagi heavier....?!