Cap 100 % hypo propylene, the elastic behind allows easy customization.

Charlotte elasticated, lightweight, wrap, made from a material non-irritating to skin with an elastic of latex covered with polypropylene

Non-woven polypropylene 16/17 g/m ² white. Elastic thread covered with polypropylene.
The Polypropylene is chemically unreactive and generally regarded as biologically
Sluggish, it is recognized to be generally anti-allergenic and is used for several years for the preparation of articles intended to be in touch with the skin. 

Nevertheless, a particularly sensitive subject can require the custom (usage) of a different material in the contact of the skin.