Cont Chk Ver Std in H2O, solution B only 3 comp, (µg/mL) Silicon, Sulfur/Sulphur at 500, Sodium at 810 (varies slightly) in H2O. 12 months expiry date. Traceable to NIST SRM 31XX series. ISO 9001:2015 certified, ISO/IEC 17025:2017 and ISO 17034:20166 acc
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