SAFETY MATERIAL: These RV water heater anode rods are made from 99.8% extra durable magnesium. Non-toxic, harmless to human body. Compared to aluminum (a common material for RV water heater anode rods), it is safer, and magnesium is not potentially hazardous. They are safe for you and your family. Compatibility: These magnesium anode rods are 9.25inch long, come with 3/4inch NPT threads, and are compatible with water tanks and Mor-Flo. The rods use a 1 1/16inch socket. Not compatible with 1/2inch thread or 4inch long rod. Please note: replacing the anode rod before the heater operates will slow corrosion to inside the water tank and will greatly extend the life of the water heater, sometimes even doubling. Anode rods should be replaced regularly in 6 months to 1 year, keep a spare in your RV. Quantity: 2 pieces Colour: silver