4x6 labels refer to adhesive labels 4 inches in width and 6 inches in height. These labels are commonly used for printing shipping, address, and product labels. They can be printed using a thermal or inkjet printer and usually come in rolls or sheets. 4x6 labels are compatible with many popular label printing software, such as Avery and DYMO. They can also be customized with logos, text, and barcodes to meet specific labeling requirements.