KF25 flange pressure relief valve for vacuum chamber, improved version (< 1.5 Psig)The valve body is made of 1 pc CNC, reducing potential leak Prevent excessive positive pressure build up in pumps or vacuum chambers Spring loaded piston pushed open when chamber pressure > 1. 5 psig or 16. 2 psia or 1116 mbar Spring loaded piston close when chamber pressure < 16. 2 psia (1. 5psig) or 1116 mbar Piston open @ PISA = 16. 2 psia + 0. 3 PSI or 1. 5 psig + 0. 3 PS Made of stainless steel 304