The 6" Watts 995RPDA Reduced Pressure Detector Assembly (RPDA) was produced from 1999-2003. The body was made of stainless steel and features a one cover design. Modular check assemblies thread into body. The relief valve sets directly below the cover and uses an external sensing line. Bypass device shall be a 3/4" Watts 995 or 3/4" Watts 009M3. No special tools are required for servicing.