Make sure your packages get where they're supposed to go without any confusing markings showing through when you use these shipping labels. TrueBlock Technology completely covers everything underneath. The adhesive sticks to more tough surfaces, ensuring your label doesn't fall off your package. It's easy to create custom labels with logos, barcodes and more. Just print your labels right from your own printer. It's easier than ever to get the job done right. Label Size - text: 2 x 4; Label Color(s): White; Machine Compatibility: Laser Printers; Catalog Description: Shipping.