Fluorescent Penetrant MET-L-CHEK FP-921 – Sensitivity 1 – Penetrant for general metal working inspection, also approved for use in aircraft industry by Boeing BSS 7039 & BAC 20-20-0, Pratt & Whitney FPM PMC #4353-AG, General Electric Aircraft Engines 70-32-02 & Gas Turbines LM6000 PC 11, Rolls-Royce RPS-702-7.