This vintage Chromalox R5135B water heater thermostat is a great find for anyone looking for a high-quality replacement part. With its line voltage type and United States origin, this thermostat is sure to meet all your HVAC and refrigeration needs. The model is specifically designed for use with electric water heaters and is marked as NOS, or not otherwise sold, in its original box. Whether you're a professional HVAC and refrigeration technician or a DIY enthusiast, this Chromalox R5135B water heater thermostat is a must-have for your collection. It is perfect for those looking to restore their vintage heating system or replace a faulty part. Don't miss out on this opportunity to own a piece of HVAC and refrigeration history.