Heyrex Torus Self-Filling Pet Water Bowl, 1 Liter, Portable, Carbon-Filtered CONSTANT SUPPLY OF CLEAN, FRESH DRINKING WATER: The wall of the bowl holds a 1-litre reservoir of water which passes through the innovative filter and auto-replenishes as your pet drinks. COOLER FOR LONGER: The thick walls of the TORUS bowl are insulated to ensure your pets drinking water stay cooler for longer. IDEAL FOR CATS & SMALL DOGS: The TORUS bowl is designed to replenish as often as your pet drinks from the bowl so that the water doesnt go tepid or stale. TRAVEL FRIENDLY: Designed with a sleek, stable profile and non-slip rubber foot pads, the TORUS bowl will not easily spill or tip. EASY TO CLEAN: If the water gets hairy, simply lock the filter and clean the bowl out without wasting all the water. Once clean, simply unlock the filter and the well will fill up from the reservoir. Quarter gallon water capacity Auto-replenishes Filters water Water fill, flow and lock options Travel friendly Stored water protection No mess, no spill or splashes Ergonomic design Made from food-grade materials Easy to clean Fresh and cool filtered water for your dog Space conscious 1/4 gallon, 1qt, 32oz size Travel-friendly, take your Torus water bowl anywhere Less splash mess because it maintains a low water level Solid construction, doesn&#039;t tip over and requires no batteries or electricity. Water is gravity fed