S size measures 66-75cm and fits a 65-75A/B.
M size measures 68-77cm and fits a 70-75B/C.
L size measures 70-80cm and fits a 80C/D.
Things to take note of
The band is not as stretchy as the regular bralettes
Additional ^ straps that surround the cup
Contrasting lace pattern on cups and underband
Adjustable shoulder straps