These swab boxes are made of 18pt, virgin fiber, solid bleached sulfate. This stock helps prevent cross contamination and is the sturdiest swab box available. Boxes are pre-cut with 2 breathing holes. Contains no biodegradable components to jeopardize the evidence. The breathable boxes are ideal for cotton tipped swabs, Cap-shure™ swabs and our Bio-Swab. Simply squeeze the box and the box pops up to prevent contamination.