12\” Wafer Check Cast Steel /Stainless Steel with Buna Seat 150# Dual Disc Titan CV42CSB 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 applications.