A stand-alone oxygen optode with integrated temperature sensor, manufactured by Aanderaa. This instrument exploits the physio-chemical principle of dynamic fluorescence quenching to measure absolute oxygen concentration and percent saturation. Depth rating: 300 m, 3000 m or 6000 m; oxygen concentration accuracy of < 8 uM or 5 %, and resolution of < 1 uM; air saturation accuracy of < 5 %, and resolution of 0.4 %; response time (63 %): < 8 s.