Avery Shipping Address Labels, Laser Printers, 600 Labels, 3-1/3x4 Labels, Permanent Adhesive, TrueBlock (5164) Permanent adhesive guaranteed to stick and stay put on cardboard, envelopes, paper, glass or metal. No more jams or smudges with Avery shipping labels. White labels optimized for laser printers. TrueBlock technology covers up everything underneath the shipping label so you can reuse boxes. Easily customize these printable labels with thousands of free templates and designs at avery.com/templates. Great for bulk shipping and mailing, organizing boxes, bin labels, classroom organization & stickers, filing & organizing, and bottle labels. TrueBlock Technology completely covers everything underneath Labels are bright white for professional results every time Jam-free and smudge-free printing is guaranteed Smooth-feed sheet edges prevent buildup that causes printer jams Customize with free tools, software and templates from avery's Website