5.250" overall length econ-o-trol dia-seal piston model water-tight housing (NEMA4) ; u.s. std. adj. range 25-500 psi, u.s. std. proof press, 1000 psi, metric proof, press- 69.0 bar, metric adj. range 1.72-345 bar; viton diaphragm; 1/4 inch npt internal thread; for g.m. diesel engine model 20-645-e-4, serial number 76-K1-1066 rectangular