for (40-622) 700 X 38c tube
2 507 02
The 40 is the inflated width in mm and the 622 is the internal diameter in mm.
It’s the international standard ISO-5775 for tire sizes.
In brackets are the French size (700mm outer diameter x 38mm width)
and the Inch size (28 outer diameter x 1 5/8 height x 1 1/2 width)