1-3/8" Diameter (35mm) low gluten wafers are approved for use in the Catholic Mass by the United States Conference of Catholic Bishops. They are made of wheat starch and water. The gluten content of our low gluten wafer is below 20 parts per million. The baking of the low gluten wafers is done in a dedicated bakery using positive air pressure to create a room that is totally free of contaminants. The equipment is also dedicated to the low gluten baking and is not used for regular altar bread production. They are packaged in boxes of 25 individually wrapped wafers to prevent cross contamination in transit and while stored. Shelf life is guaranteed for 1 year.