Esporta's & Estrella's have 2 removable under soles (2) below the insole (1), allowing you to adjust the size and customize the fit.

With 1 under sole (2) in the shoe, the shoe fits true to size.
Remove both under soles (2) to make the shoe fit 1/2 size larger.
Add both under soles (2) to make the shoe fit 1/2 size smaller.