Check valve Manufacturers from USA/Europe/Korea. Sizes:  1/2" up to 36" Pressure: Class 150 to API 15K. Material: Carbon steel, stainless steel, Aluminium Bronze to exotic Duplex SS, Monel and etc. Different types:  Swing Check Valve, Dual Plate Check Valve and Non-slam nozzle check. Check valve design according to API 594, API 6D, API 600 and BS1868