Fury Now with the Guardian System--------------------------------------------------------------------------------Available Capacities:30, 40, 50 gallon Tall - 30 and 40 gallon short modelsAvailable Warranties:6-year limited tank and parts warranty: With ProtectionPlus the 6-year limited tank warranty becomes 10 years!--------------------------------------------------------------------------------Features:Guardian System - One-of-a-kind air/fuel shut-off device offers double protection, maintenance free - no filter to clean, standard replacement parts. Low NOx design for low nitous oxide emissions Self-Cleaning - EverKleen patented system fights sediment build-up, reduces fuel costs, provides more hot water. Easy to Light - no matches required Energy Efficient - more hot water at low operating cost Longer Life - Patented magnesium anode rod design incorporates a special resistor that protects the tank from rust. High Altitude Compliant - All models are certified for applications up to 6,000 feet above sea level. Some models are certified up to 10,200 feet above sea level. Brass drain valve and temperature and pressure relief valve included. Upgrade your warranty with ProtectionPlus and your 6-year limited tank warranty becomes a 10 year.