What is the purpose of a washer box with hammer arrestor and how does it prevent water hammer in plumbing systems?

The purpose of a washer box with hammer arrestor is to prevent water hammer in Plumbing systems. Water hammer is a loud banging noise that occurs when water flow is suddenly stopped or redirected in a pipe. The hammer arrestor in the washer box absorbs the shock caused by the sudden change in water flow, preventing the noise and potential damage to the plumbing system.