Size: 4" x 6" fanfold labels, 4 stacks of 4000 labels total, 1 stack = 1000 Labels. Direct thermal labels with blue background paper, simple to differentiate. Blank mailing label with a perforated line for easy peeling. Resists scratches, water, dirt, dust, and grease. Strong permanent adhesive for boxes, mailers, envelopes, cardboard, cardstock, paper, and plastic. Just peel and stick without needing packing tape. Postage labels are made from high-quality material to ensure clear image prints and easy barcode scanning. Compatible with Zebra, Intermec, Datamax, Printronix, and other direct thermal printers capable of accepting the 4x 6 dimensions