Measurements: Label size: 4" x 6" (101mm x 152mm) - 500 labels per roll Our white direct thermal labels are produced on the best thermal paper material available and using a high quality adhesive. 4 x 6 thermal labels are 4 inches wide and 6 inches long, presented narrow edge leading out of the label printer, most of the common courier label printers are a 4" wide configuration so this give the best use of the maximum print width and the additional length of 6 inches on the label gives plenty of space for the address details, tracking details and barcodes required for the internal courier hub routing procedures and end to end package tracking.