|Since 1856, A.Y. McDonald Mfg. Co. has been providing the solution to make water work for you and your community. By trusting in our many years of experience and talented team of experts, be prepared to invest in some of the best corporation (corp) stops out there. A corp stop is the initial control valve for the service line, allowing for the installation of a new water service line without interrupting the water main pressure. For product inquiries and ordering information, feel free to contact us.