Amazon.com : Pack of 25 - Pallet Rack Sign Holder with Two Magnetic Strips, Vinyl Pouch Label Holder with Side Opening, Rack & Shelf Card Holders, Size 3-1/2" Height x 5-1/2" Wide :
Quick Tips for Warehouse Rack Labeling Systems - Stop-Painting.com Blog
4 Proven Options for Relabeling Warehouse Racks - ID Label Inc.