Free Flo, Heavy Duty, Livestock Plastic Watering Valve, No Float, Rod Or Guard Needed, Approved Non-Siphoning, Fits All Tanks Or Troughs, Automatically Maintains Water Level, Protected From Surface Freezing, Completely Corrosion-Proof, 16" Water Level Adjusting Knob, Easily Installed In New Or Existing System, Hook-Up 1/4" Copper Pipe, 1/2" Metal Pipe, Garden Hose Or 1" PVC Adapter Fitting, Full 1-Year Guarantee.