Cyclonic makes in-line check valves with O-ring seating optional, 4.5" end-to-end, 2" to 4" NPT, and wafer bodies. They are constructed of 4140 alloy steel, 316 stainless steel, or 9D aluminum bronze, available in 2000 cwp or 3000 cwp. Products are a one-piece design with metal seating and 1/4 port standard.