2" Non-CFC foam insulation; 51 gallon first hour rating Uniform Energy Factor (UED); Recovery 21 gallon per hour at 90 degree rise, Diffuser-End pex dip tube; Glass-lined tank premium grade anode rod protects against tank corrosion, Ace RSC available replacement parts: elements Ace 40314, Upper thermostat Ace 44983, Lower thermostat Ace 44981, T&P valve Ace 4008611, NOTE: Dimensions and specifications subject to change without notice in accordance with Reliance Water Heaters policy of continuous product improvement