This is a great way to buy silk fibre for needlefelting, spinning, silk paper or just to have.  Caps are made by pulling boiled off cocoons over a arch shaped frame.  Many cocoons go into one cap and they lightly compress or bond to each other.  This means you can either use this as a fabulous base fabric or you can peel off layers, right down to a single cocoon size.

Each cap is a different size.  Large ones are about 30 to 40 grams and are sold individually, smaller ones are sold in packs of two.