Made of a tough poly for durability with a mesh bottom that allows dirt to escape, the Cashel Slow Feed Top Load Hay Bag hangs conveniently on a fence or in your trailer. You can load it with one hand, and the top strap velcros shut so hay doesn't come out the top. A no-spin, adjustable back strap keeps the bag in place. Each opening is approximately 2.5" x 2.5".