55 Gallon W-Series Stock Tank is rotationally molded with high quality, FDA approved, UV protected, impact resistant Poly to ensure uniform thickness and strength for unrivaled durability. All edges have been rounded for animal safety. The one piece construction eliminates cracking and splitting that's common in plastic-welded, two piece tanks. If the Stock Tank gets a small leak due to unforeseen circumstances, such as a bullet hole, it can be braze welded with a common butane torch to fill the hole. Industry leading 5 year warranty that is backed 100% from the date of purchase.