Freeland Free Flo Automatic Fill Valve fits all types of water tanks, (wood, steel, ceramic, plastic, etc.) up to 1/2 inch wall thickness. Water level is adjustable 4 in. to 20 in. above the valve. Mounts in sidewall of bottom of tank, out of reach of livestock. No float, rod or guard needed. Approved non-siphoning. Automatically maintains water level. Protected from surface freezing, completely corrosion proof. 16 in. water level adjusting knob.  Easily installed in new or existing system. Hook-up 1/4 in. copper pipe, 1/2 in. metal pipe, garden hose or 1 in. PVC adapter fitting.