This Watts repair kit is designed for use with specific pressure reducing valves, specifically models 152A and 252A with sizes 1-1/2" and 2". The kit contains components necessary for the maintenance of these valves, including a stem and bushing assembly, diaphragm, diaphragm gasket, bottom plug gasket, bottom spring, strainer, disc, and seat. These parts are used to replace worn or damaged components in the valve assembly to ensure proper function.