Our cartridge labels are made of adhesive-backed mylar, a waterproof and stain-resistant plastic. These labels are in roll format (500 per roll) for easy dispensing. The labels are not shown here actual size. We design our labels with precision: sized to fit either over the OEM if left in place, or as a replacement. Many cartridges use the label to cover vent holes on the cap. Our labels are sized to accommodate this.