The Waterco 2 inch half union with O-ring for 1-1/2 inch slip Trimline applications is designed for compatible plumbing systems where the union side of the connection needs the correct model-specific replacement. A half union is useful because it provides a service-friendly connection point that can be separated without cutting the plumbing apart.This replacement is especially useful when the original fitting is damaged, worn, or no longer sealing properly in the Trimline setup. The included O-ring helps complete the service part and supports a more dependable repair without turning a simple union replacement into a parts hunt.The 122257BLK is a smart choice when a compatible Trimline configuration needs the correct Waterco union component restored with proper fit and sealing support. Waterco 2 inch half union with O-ring for 1-1/2 inch slip Trimline applications Designed for compatible serviceable plumbing connections Helps restore correct union fit and sealing Useful when the original fitting is cracked, worn, or leaking Includes O-ring for a more complete repair