4" Wafer Check Ductile Iron /Bronze with Buna Seat 150/300# Dual Disc Titan CV41DBB4" Wafer Check Ductile Iron Bronze with Buna Seat 150 300# Dual Disc Titan CV41DBB Minimal Head Loss Quick Closure to Reduce Water Hammer Resilient Soft Seats BUNA N PROPERTIES: most widely used elastomer. good for most petroleum oils and fluids, silicone greases and oils, and cold water. excellent compression set, tear, and abrasion resistance . poor weather resistance and moderate heat resistance . not recommended for severe ozone resistant