By definition the professional ones are the ones made with 8 layers on the skirt and a circumference of 35/40 cm. The semi professional ones are in between the basic ones and the professional ones. Compared to the basic ones, the semi professionals present a Longer corolla, more decorations and more layers on the skirt (often hard tulle). The professional, present a more detailed manufacture like the layers are stitched, making the tulle move in a more elegant way as the Ballerina dances.
The circumference of the corolla will be personalized according to the height of the Ballerina to make sure the product is perfectly fitting the dancer.
This is why we picked the length based on the size but if there's a particular length needed, please let us know before you order it!