Comply with shipping regulations by using Labelmaster over Pack labels. Overpacks containing dangerous goods are required to be marked with the word "over Pack" in Association with the proper shipping name. This rule is effective for international air and sea shipments; is required for shipment in the U.S.; and is used very often for ground shipments. Printed on paper, these air labels have outstanding chemical and abrasion resistance, feature strong adhesion, and help keep you in regulatory compliance. They measure 6 x 2 1/2 in.