The ID plate on the hydrogen peroxide tank. The undamaged portion of the ID plate reads (rotated 180 degrees for readability)
Max. Working Pressure 825 P.S.I. Part No. Serial No. N.A. 72451 P.004 Weight Empty Date <blank> 1-15-58 Contract No. Model No. 9572 <blank> Inspectors Mfg. By