Synapse Synchronic Blow Off Valve is a first to revolutionize the blow off valve industry. Unlike other blow off valves on the market, this BOV does not use a diaphragm which give it unparallel response and eliminates compressor surge. It features a pull type piston actuated design and poppet valve for maximum flow at initial opening. Includes stainless steel weld-on flange. Other flanage available separately.