Cla-Val Series RF-DBJ Duckbill Jacket Style Check Valves feature all-metal enclosures for installation in pipelines as a whisper-quiet, non-slamming, low-maintenance, low pressure-drop check valve. A variety of elastomers allow DBJ valves to be used with many different fluids. When ordering, specify Model DBJ, nominal pipe, flange drilling and add first letter of elastomer material i.e.: 4″-DBJ-N (N for Neoprene).