c:\my files\diving\Tank markings
3AA - Steel
2250 - Service Pressure (PSI)
SN - 199133
1st inspection/MFR symbol - 4 N 70+ (+ = test + 10% pressure)
1st inspection - 4 - Month 70 - year
+ - may be filled will 10% extra pressure
Inspected by symbol - N (Norris) /