1. Label size: <b>4"x6", 1" core, with perforated line</b>. <br> <br> 2. The 4x6 direct thermal shipping labels are 100% compatible with zebra eltron printers. <br> <br> 3. The direct thermal mailing labels are <b>very adhesive</b> on boxes and envelopes. <br> <br> 4. MFLABEL Company is factory direct sell. Our labels are all with <b>competitive price and premium quality</b>. <br> <br> 5. We can accept <b>custom all kinds of barcode shipping mailing labels</b>. <br> <br> 6. If you have problem on the printer setup or label use, please contact us via Amazon message. We will give you a suggestion.<br> <br> 7. <b>Please note that the labels are very sticky, so you do not need tape the packing tapes. There is a chemical reaction between tape and the glue of labels.</b>