ProCage batting cages are constructed of heavy synthetic HDPE fiber which is extruded with a Permanent Black Color and with very important Sunlight/U.V. Inhibitors throughout each filament. Our netting is manufactured using extremely high abrasion resistant twisted knotted netting, the strongest form of netting in commercial use. What makes our netting better: 3 Year Warranty on most popular sizes. Permanent Black Color : Each filament is extruded black - will not fade or need re-dying. 100% waterproof : The absolute best filament for Outdoor Use. U.V. Protected : U.V. additives extruded directly into filament. Not a coating that will wear off or require re-treating. Twisted Knotted construction : Strongest form of netting in commercial use. Will not run if cut. Very High Abrasion Resistance : The biggest factor in long-term tunnel use. Low-stretch : No drooping overhead ceiling or having to re-hang net due to stretch or sag. Hung Square : (Like tennis nets) Rated best for appearance. Allows tunnel to open fully and hang straight. Most expensive to produce but best for reinforced edges, corners and seams. Rope reinforcement : All edges, corners and top hanging ropes use heavy synthetic rope with machine-sewn over lock-stitch. No rope slippage. More durable than vinyl borders(more.).