balletballet says:

Basic boys matt shorts, perfect for all styles of dance. 

Manufacturer says:
1st Position Boys Ballet Shorts
Narrow elastic on the waistband to give a smooth finish when worn with a leotard.
Fabric:  80% Nylon 20% Elastane in a MATT finish
Keep away from fire.
Designed as dancewear.

Concerned about getting the right fit? Of course, we understand, check our sizing charts .