The Bradford White Corporation LP to Natural Gas Conversion Kit (part number 265-53745-23) is specifically designed for the M4403S/M4503 models with high altitude FVIR technology. This kit facilitates the conversion from LP to natural gas, ensuring compatibility with various gas supply systems. It includes all necessary components for a seamless installation, adhering to industry standards for safety and performance. Constructed from durable materials, this conversion kit enhances the versatility of your water heater, making it suitable for different gas types.