Wilkins: 2 1/2" - 4" - Second Check Seat Retainer for a 350A / 350 / 450 Double Check Assembly {OR} 375A/ 475/ 375 Reduced Pressure Zone Assembly
• 2 1/2" - 4" check seat retainer for models 350A / 375A
• 4" check seat retainer for models 350 / 375 / 450 / 475
(Two are required for one backflow assembly)