Guardhouse plastic coin holders are made of three parts, an insert and two sides that form the case. Insert a coin into the black foam insert, then snap the two sides shut. The insert and case of each plastic 2x2 are acid free and archival safe. The foam inserts are vinyl free. Guardhouse holders are notched to allow for easy opening, and every holder can be reused many times. These holders fit in any of our 2x2 storage boxes.